/******************************************************************************
 *
 * Project:  Elasticsearch Translator
 * Purpose:
 * Author:
 *
 ******************************************************************************
 * Copyright (c) 2011, Adam Estrada
 * Copyright (c) 2012-2016, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "ogr_elastic.h"
#include "cpl_conv.h"
#include "cpl_minixml.h"
#include "cpl_http.h"
#include "ogr_api.h"
#include "ogr_p.h"
#include "ogr_swq.h"
#include "ogrgeojsonwriter.h"
#include "ogrlibjsonutils.h"
#include "ogrgeojsongeometry.h"
#include "ogr_geo_utils.h"

#include <cstdlib>
#include <set>

/************************************************************************/
/*                        CPLGettimeofday()                             */
/************************************************************************/

#if defined(_WIN32) && !defined(__CYGWIN__)
#include <sys/timeb.h>

struct CPLTimeVal
{
    time_t tv_sec; /* seconds */
    long tv_usec;  /* and microseconds */
};

static void CPLGettimeofday(struct CPLTimeVal *tp, void * /* timezonep*/)
{
    struct _timeb theTime;

    _ftime(&theTime);
    tp->tv_sec = static_cast<time_t>(theTime.time);
    tp->tv_usec = theTime.millitm * 1000;
}
#else
#include <sys/time.h> /* for gettimeofday() */
#define CPLTimeVal timeval
#define CPLGettimeofday(t, u) gettimeofday(t, u)
#endif

static double GetTimestamp()
{
    struct CPLTimeVal tv;
    CPLGettimeofday(&tv, nullptr);
    return tv.tv_sec + tv.tv_usec * 1e-6;
}

/************************************************************************/
/*                           OGRElasticLayer()                          */
/************************************************************************/

OGRElasticLayer::OGRElasticLayer(const char *pszLayerName,
                                 const char *pszIndexName,
                                 const char *pszMappingName,
                                 OGRElasticDataSource *poDS,
                                 CSLConstList papszOptions,
                                 const char *pszESSearch)
    :

      m_poDS(poDS), m_osIndexName(pszIndexName ? pszIndexName : ""),
      // Types are no longer supported in Elasticsearch 7+.
      m_osMappingName(poDS->m_nMajorVersion < 7
                          ? pszMappingName ? pszMappingName : ""
                          : ""),
      m_poFeatureDefn(new OGRFeatureDefn(pszLayerName)),
      m_osWriteMapFilename(
          CSLFetchNameValueDef(papszOptions, "WRITE_MAPPING",
                               poDS->m_pszWriteMap ? poDS->m_pszWriteMap : "")),
      m_bStoreFields(CPLFetchBool(papszOptions, "STORE_FIELDS", false)),
      m_osESSearch(pszESSearch ? pszESSearch : ""),
      m_nBulkUpload(poDS->m_nBulkUpload),
      m_osPrecision(CSLFetchNameValueDef(papszOptions, "GEOM_PRECISION", "")),
      // Undocumented. Only useful for developers.
      m_bAddPretty(CPLTestBool(CPLGetConfigOption("ES_ADD_PRETTY", "FALSE"))),
      m_bGeoShapeAsGeoJSON(EQUAL(
          CSLFetchNameValueDef(papszOptions, "GEO_SHAPE_ENCODING", "GeoJSON"),
          "GeoJSON"))
{
    const char *pszESGeomType =
        CSLFetchNameValue(papszOptions, "GEOM_MAPPING_TYPE");
    if (pszESGeomType != nullptr)
    {
        if (EQUAL(pszESGeomType, "GEO_POINT"))
            m_eGeomTypeMapping = ES_GEOMTYPE_GEO_POINT;
        else if (EQUAL(pszESGeomType, "GEO_SHAPE"))
            m_eGeomTypeMapping = ES_GEOMTYPE_GEO_SHAPE;
    }

    if (CPLFetchBool(papszOptions, "BULK_INSERT", true))
    {
        m_nBulkUpload =
            atoi(CSLFetchNameValueDef(papszOptions, "BULK_SIZE", "1000000"));
    }

    const char *pszStoredFields =
        CSLFetchNameValue(papszOptions, "STORED_FIELDS");
    if (pszStoredFields)
        m_papszStoredFields = CSLTokenizeString2(pszStoredFields, ",", 0);

    const char *pszNotAnalyzedFields =
        CSLFetchNameValue(papszOptions, "NOT_ANALYZED_FIELDS");
    if (pszNotAnalyzedFields)
        m_papszNotAnalyzedFields =
            CSLTokenizeString2(pszNotAnalyzedFields, ",", 0);

    const char *pszNotIndexedFields =
        CSLFetchNameValue(papszOptions, "NOT_INDEXED_FIELDS");
    if (pszNotIndexedFields)
        m_papszNotIndexedFields =
            CSLTokenizeString2(pszNotIndexedFields, ",", 0);

    const char *pszFieldsWithRawValue =
        CSLFetchNameValue(papszOptions, "FIELDS_WITH_RAW_VALUE");
    if (pszFieldsWithRawValue)
        m_papszFieldsWithRawValue =
            CSLTokenizeString2(pszFieldsWithRawValue, ",", 0);

    const char *pszSingleQueryTimeout =
        CSLFetchNameValue(papszOptions, "SINGLE_QUERY_TIMEOUT");
    if (pszSingleQueryTimeout)
    {
        m_dfSingleQueryTimeout = CPLAtof(pszSingleQueryTimeout);
        if (m_dfSingleQueryTimeout < 1 && m_dfSingleQueryTimeout >= 1e-3)
            m_osSingleQueryTimeout = CPLSPrintf(
                "%dms", static_cast<int>(m_dfSingleQueryTimeout * 1000));
        else if (m_dfSingleQueryTimeout >= 1)
            m_osSingleQueryTimeout =
                CPLSPrintf("%ds", static_cast<int>(m_dfSingleQueryTimeout));
    }

    m_osSingleQueryTerminateAfter =
        CSLFetchNameValueDef(papszOptions, "SINGLE_QUERY_TERMINATE_AFTER", "");
    m_nSingleQueryTerminateAfter = CPLAtoGIntBig(m_osSingleQueryTerminateAfter);

    const char *pszFeatureIterationTimeout =
        CSLFetchNameValue(papszOptions, "FEATURE_ITERATION_TIMEOUT");
    if (pszFeatureIterationTimeout)
    {
        m_dfFeatureIterationTimeout = CPLAtof(pszFeatureIterationTimeout);
    }
    m_nFeatureIterationTerminateAfter = CPLAtoGIntBig(CSLFetchNameValueDef(
        papszOptions, "FEATURE_ITERATION_TERMINATE_AFTER", ""));

    SetDescription(m_poFeatureDefn->GetName());
    m_poFeatureDefn->Reference();
    m_poFeatureDefn->SetGeomType(wkbNone);

    AddFieldDefn("_id", OFTString, std::vector<CPLString>());

    if (!m_osESSearch.empty())
    {
        AddFieldDefn("_index", OFTString, std::vector<CPLString>());
        AddFieldDefn("_type", OFTString, std::vector<CPLString>());
    }

    OGRElasticLayer::ResetReading();
}

/************************************************************************/
/*                           OGRElasticLayer()                          */
/************************************************************************/

OGRElasticLayer::OGRElasticLayer(const char *pszLayerName,
                                 OGRElasticLayer *poReferenceLayer)
    : OGRElasticLayer(pszLayerName, pszLayerName,
                      poReferenceLayer->m_osMappingName,
                      poReferenceLayer->m_poDS, nullptr)
{
    m_bAddSourceIndexName = poReferenceLayer->m_poDS->m_bAddSourceIndexName;

    poReferenceLayer->CopyMembersTo(this);
    auto poFeatureDefn = new OGRFeatureDefn(pszLayerName);
    if (m_bAddSourceIndexName)
    {
        OGRFieldDefn oFieldDefn("_index", OFTString);
        poFeatureDefn->AddFieldDefn(&oFieldDefn);
#if defined(__GNUC__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnull-dereference"
#endif
        m_aaosFieldPaths.insert(m_aaosFieldPaths.begin(),
                                std::vector<CPLString>());
#if defined(__GNUC__)
#pragma GCC diagnostic pop
#endif
        for (auto &kv : m_aosMapToFieldIndex)
        {
            kv.second++;
        }
    }

    {
        const int nFieldCount = m_poFeatureDefn->GetFieldCount();
        for (int i = 0; i < nFieldCount; i++)
            poFeatureDefn->AddFieldDefn(m_poFeatureDefn->GetFieldDefn(i));
    }

    {
        // Remove the default geometry field created instantiation.
        poFeatureDefn->DeleteGeomFieldDefn(0);
        const int nGeomFieldCount = m_poFeatureDefn->GetGeomFieldCount();
        for (int i = 0; i < nGeomFieldCount; i++)
            poFeatureDefn->AddGeomFieldDefn(
                m_poFeatureDefn->GetGeomFieldDefn(i));
    }

    m_poFeatureDefn->Release();
    m_poFeatureDefn = poFeatureDefn;
    m_poFeatureDefn->Reference();

    CPLAssert(static_cast<int>(m_aaosFieldPaths.size()) ==
              m_poFeatureDefn->GetFieldCount());
    CPLAssert(static_cast<int>(m_aaosGeomFieldPaths.size()) ==
              m_poFeatureDefn->GetGeomFieldCount());
}

/************************************************************************/
/*                            CopyMembersTo()                           */
/************************************************************************/

void OGRElasticLayer::CopyMembersTo(OGRElasticLayer *poNew)
{
    FinalizeFeatureDefn();

    poNew->m_poFeatureDefn->Release();
    poNew->m_poFeatureDefn =
        const_cast<OGRElasticLayer *>(this)->GetLayerDefn()->Clone();
    poNew->m_poFeatureDefn->Reference();
    poNew->m_bFeatureDefnFinalized = true;
    poNew->m_osBulkContent = m_osBulkContent;
    poNew->m_nBulkUpload = m_nBulkUpload;
    poNew->m_osFID = m_osFID;
    poNew->m_aaosFieldPaths = m_aaosFieldPaths;
    poNew->m_aosMapToFieldIndex = m_aosMapToFieldIndex;
    poNew->m_aaosGeomFieldPaths = m_aaosGeomFieldPaths;
    poNew->m_aosMapToGeomFieldIndex = m_aosMapToGeomFieldIndex;
    poNew->m_abIsGeoPoint = m_abIsGeoPoint;
    poNew->m_eGeomTypeMapping = m_eGeomTypeMapping;
    poNew->m_osPrecision = m_osPrecision;
    poNew->m_papszNotAnalyzedFields = CSLDuplicate(m_papszNotAnalyzedFields);
    poNew->m_papszNotIndexedFields = CSLDuplicate(m_papszNotIndexedFields);
    poNew->m_papszFieldsWithRawValue = CSLDuplicate(m_papszFieldsWithRawValue);
    poNew->m_bGeoShapeAsGeoJSON = m_bGeoShapeAsGeoJSON;
    poNew->m_osSingleQueryTimeout = m_osSingleQueryTimeout;
    poNew->m_dfSingleQueryTimeout = m_dfSingleQueryTimeout;
    poNew->m_dfFeatureIterationTimeout = m_dfFeatureIterationTimeout;
    poNew->m_nSingleQueryTerminateAfter = m_nSingleQueryTerminateAfter;
    poNew->m_nFeatureIterationTerminateAfter =
        m_nFeatureIterationTerminateAfter;
    poNew->m_osSingleQueryTerminateAfter = m_osSingleQueryTerminateAfter;
}

/************************************************************************/
/*                              Clone()                                 */
/************************************************************************/

OGRElasticLayer *OGRElasticLayer::Clone()
{
    OGRElasticLayer *poNew =
        new OGRElasticLayer(m_poFeatureDefn->GetName(), m_osIndexName,
                            m_osMappingName, m_poDS, nullptr);
    CopyMembersTo(poNew);
    return poNew;
}

/************************************************************************/
/*                         ~OGRElasticLayer()                           */
/************************************************************************/

OGRElasticLayer::~OGRElasticLayer()
{
    OGRElasticLayer::SyncToDisk();

    OGRElasticLayer::ResetReading();

    json_object_put(m_poSpatialFilter);
    json_object_put(m_poJSONFilter);

    for (int i = 0; i < (int)m_apoCT.size(); i++)
        delete m_apoCT[i];

    m_poFeatureDefn->Release();

    CSLDestroy(m_papszStoredFields);
    CSLDestroy(m_papszNotAnalyzedFields);
    CSLDestroy(m_papszNotIndexedFields);
    CSLDestroy(m_papszFieldsWithRawValue);
}

/************************************************************************/
/*                              AddFieldDefn()                          */
/************************************************************************/

void OGRElasticLayer::AddFieldDefn(const char *pszName, OGRFieldType eType,
                                   const std::vector<CPLString> &aosPath,
                                   OGRFieldSubType eSubType)
{
    OGRFieldDefn oFieldDefn(pszName, eType);
    oFieldDefn.SetSubType(eSubType);
    if (eSubType == OFSTBoolean)
        oFieldDefn.SetWidth(1);
    m_aaosFieldPaths.push_back(aosPath);
    if (!aosPath.empty())
        m_aosMapToFieldIndex[BuildPathFromArray(aosPath)] =
            m_poFeatureDefn->GetFieldCount();
    m_poFeatureDefn->AddFieldDefn(&oFieldDefn);
}

/************************************************************************/
/*                           AddGeomFieldDefn()                         */
/************************************************************************/

void OGRElasticLayer::AddGeomFieldDefn(const char *pszName,
                                       OGRwkbGeometryType eType,
                                       const std::vector<CPLString> &aosPath,
                                       int bIsGeoPoint)
{
    OGRGeomFieldDefn oFieldDefn(pszName, eType);
    m_aaosGeomFieldPaths.push_back(aosPath);
    m_aosMapToGeomFieldIndex[BuildPathFromArray(aosPath)] =
        m_poFeatureDefn->GetGeomFieldCount();
    m_abIsGeoPoint.push_back(bIsGeoPoint);

    OGRSpatialReference *poSRS_WGS84 = new OGRSpatialReference();
    poSRS_WGS84->SetFromUserInput(SRS_WKT_WGS84_LAT_LONG);
    poSRS_WGS84->SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
    oFieldDefn.SetSpatialRef(poSRS_WGS84);
    poSRS_WGS84->Dereference();

    m_poFeatureDefn->AddGeomFieldDefn(&oFieldDefn);

    m_apoCT.push_back(nullptr);
}

/************************************************************************/
/*                       GetGeomFieldProperties()                       */
/************************************************************************/

void OGRElasticLayer::GetGeomFieldProperties(int iGeomField,
                                             std::vector<CPLString> &aosPath,
                                             bool &bIsGeoPoint)
{
    aosPath = m_aaosGeomFieldPaths[iGeomField];
    bIsGeoPoint = CPL_TO_BOOL(m_abIsGeoPoint[iGeomField]);
}

/************************************************************************/
/*                     InitFeatureDefnFromMapping()                     */
/************************************************************************/

void OGRElasticLayer::InitFeatureDefnFromMapping(
    json_object *poSchema, const char *pszPrefix,
    const std::vector<CPLString> &aosPath)
{
    json_object *poTopProperties =
        CPL_json_object_object_get(poSchema, "properties");
    if (poTopProperties == nullptr ||
        json_object_get_type(poTopProperties) != json_type_object)
        return;
    json_object_iter it;
    it.key = nullptr;
    it.val = nullptr;
    it.entry = nullptr;
    json_object_object_foreachC(poTopProperties, it)
    {
        json_object *poProperties =
            CPL_json_object_object_get(it.val, "properties");
        if (poProperties &&
            json_object_get_type(poProperties) == json_type_object)
        {
            json_object *poType =
                json_ex_get_object_by_path(poProperties, "coordinates.type");
            if (poType && json_object_get_type(poType) == json_type_string &&
                strcmp(json_object_get_string(poType), "geo_point") == 0)
            {
                CPLString osFieldName;
                if (pszPrefix[0])
                {
                    osFieldName = pszPrefix;
                    osFieldName += ".";
                }
                osFieldName += it.key;

                if (m_poFeatureDefn->GetGeomFieldIndex(osFieldName) < 0)
                {
                    std::vector<CPLString> aosNewPaths = aosPath;
                    aosNewPaths.push_back(osFieldName);
                    aosNewPaths.push_back("coordinates");

                    AddGeomFieldDefn(osFieldName, wkbPoint, aosNewPaths, TRUE);
                }

                continue;
            }

            if (aosPath.empty() && m_osMappingName == "FeatureCollection" &&
                strcmp(it.key, "properties") == 0)
            {
                std::vector<CPLString> aosNewPaths = aosPath;
                aosNewPaths.push_back(it.key);

                InitFeatureDefnFromMapping(it.val, pszPrefix, aosNewPaths);

                continue;
            }
            else if (m_poDS->m_bFlattenNestedAttributes)
            {
                std::vector<CPLString> aosNewPaths = aosPath;
                aosNewPaths.push_back(it.key);

                CPLString osPrefix;
                if (pszPrefix[0])
                {
                    osPrefix = pszPrefix;
                    osPrefix += ".";
                }
                osPrefix += it.key;

                InitFeatureDefnFromMapping(it.val, osPrefix, aosNewPaths);

                continue;
            }
        }

        if (aosPath.empty() && EQUAL(it.key, m_poDS->GetFID()))
        {
            m_osFID = it.key;
        }
        else
        {
            CreateFieldFromSchema(it.key, pszPrefix, aosPath, it.val);
        }
    }

    if (aosPath.empty())
    {
        json_object *poMeta = CPL_json_object_object_get(poSchema, "_meta");
        if (poMeta && json_object_get_type(poMeta) == json_type_object)
        {
            json_object *poFID = CPL_json_object_object_get(poMeta, "fid");
            if (poFID && json_object_get_type(poFID) == json_type_string)
                m_osFID = json_object_get_string(poFID);

            json_object *poGeomFields =
                CPL_json_object_object_get(poMeta, "geomfields");
            if (poGeomFields &&
                json_object_get_type(poGeomFields) == json_type_object)
            {
                for (int i = 0; i < m_poFeatureDefn->GetGeomFieldCount(); i++)
                {
                    json_object *poObj = CPL_json_object_object_get(
                        poGeomFields,
                        m_poFeatureDefn->GetGeomFieldDefn(i)->GetNameRef());
                    if (poObj &&
                        json_object_get_type(poObj) == json_type_string)
                    {
                        OGRwkbGeometryType eType =
                            OGRFromOGCGeomType(json_object_get_string(poObj));
                        if (eType != wkbUnknown)
                            m_poFeatureDefn->GetGeomFieldDefn(i)->SetType(
                                eType);
                    }
                }
            }

            json_object *poFields =
                CPL_json_object_object_get(poMeta, "fields");
            if (poFields && json_object_get_type(poFields) == json_type_object)
            {
                for (int i = 0; i < m_poFeatureDefn->GetFieldCount(); i++)
                {
                    json_object *poObj = CPL_json_object_object_get(
                        poFields,
                        m_poFeatureDefn->GetFieldDefn(i)->GetNameRef());
                    if (poObj &&
                        json_object_get_type(poObj) == json_type_string)
                    {
                        for (int j = 0; j <= OFTMaxType; j++)
                        {
                            if (EQUAL(OGR_GetFieldTypeName((OGRFieldType)j),
                                      json_object_get_string(poObj)))
                            {
                                m_poFeatureDefn->GetFieldDefn(i)->SetType(
                                    (OGRFieldType)j);
                                break;
                            }
                        }
                    }
                }
            }
        }
    }
}

/************************************************************************/
/*                        CreateFieldFromSchema()                       */
/************************************************************************/

void OGRElasticLayer::CreateFieldFromSchema(const char *pszName,
                                            const char *pszPrefix,
                                            std::vector<CPLString> aosPath,
                                            json_object *poObj)
{
    const char *pszType = "";
    json_object *poType = CPL_json_object_object_get(poObj, "type");
    if (poType && json_object_get_type(poType) == json_type_string)
    {
        pszType = json_object_get_string(poType);
    }

    CPLString osFieldName;
    if (pszPrefix[0])
    {
        osFieldName = pszPrefix;
        osFieldName += ".";
    }
    osFieldName += pszName;

    if (EQUAL(pszType, "geo_point") || EQUAL(pszType, "geo_shape"))
    {
        if (m_poFeatureDefn->GetGeomFieldIndex(osFieldName) >= 0)
            return;

        aosPath.push_back(pszName);
        AddGeomFieldDefn(osFieldName,
                         EQUAL(pszType, "geo_point") ? wkbPoint : wkbUnknown,
                         aosPath, EQUAL(pszType, "geo_point"));
    }
    else if (!(aosPath.empty() && m_osMappingName == "FeatureCollection"))
    {
        if (m_poFeatureDefn->GetFieldIndex(osFieldName) >= 0)
            return;

        OGRFieldType eType = OFTString;
        OGRFieldSubType eSubType = OFSTNone;
        if (EQUAL(pszType, "integer"))
            eType = OFTInteger;
        else if (EQUAL(pszType, "boolean"))
        {
            eType = OFTInteger;
            eSubType = OFSTBoolean;
        }
        else if (EQUAL(pszType, "long"))
            eType = OFTInteger64;
        else if (EQUAL(pszType, "float"))
            eType = OFTReal;
        else if (EQUAL(pszType, "double"))
            eType = OFTReal;
        else if (EQUAL(pszType, "date"))
        {
            eType = OFTDateTime;
            json_object *poFormat = CPL_json_object_object_get(poObj, "format");
            if (poFormat && json_object_get_type(poFormat) == json_type_string)
            {
                const char *pszFormat = json_object_get_string(poFormat);
                if (EQUAL(pszFormat, "HH:mm:ss.SSS") ||
                    EQUAL(pszFormat, "time"))
                    eType = OFTTime;
                else if (EQUAL(pszFormat, "yyyy/MM/dd") ||
                         EQUAL(pszFormat, "date"))
                    eType = OFTDate;
            }
        }
        else if (EQUAL(pszType, "binary"))
            eType = OFTBinary;
        else if (EQUAL(pszType, "string"))  // ES < 5.0
        {
            json_object *poIndex = CPL_json_object_object_get(poObj, "index");
            if (poIndex && json_object_get_type(poIndex) == json_type_string)
            {
                const char *pszIndex = json_object_get_string(poIndex);
                if (EQUAL(pszIndex, "not_analyzed"))
                {
                    m_papszNotAnalyzedFields =
                        CSLAddString(m_papszNotAnalyzedFields, osFieldName);
                }
            }
        }
        else if (EQUAL(pszType, "keyword"))  // ES >= 5.0
        {
            m_papszNotAnalyzedFields =
                CSLAddString(m_papszNotAnalyzedFields, osFieldName);
        }

        aosPath.push_back(pszName);
        AddFieldDefn(osFieldName, eType, aosPath, eSubType);

        json_object *poFields = CPL_json_object_object_get(poObj, "fields");
        if (poFields && json_object_get_type(poFields) == json_type_object)
        {
            json_object *poRaw = CPL_json_object_object_get(poFields, "raw");
            if (poRaw && json_object_get_type(poRaw) == json_type_object)
            {
                json_object *poRawType =
                    CPL_json_object_object_get(poRaw, "type");
                if (poRawType &&
                    json_object_get_type(poRawType) == json_type_string)
                {
                    const char *pszRawType = json_object_get_string(poRawType);
                    if (EQUAL(pszRawType, "keyword"))  // ES >= 5.0
                    {
                        m_papszFieldsWithRawValue = CSLAddString(
                            m_papszFieldsWithRawValue, osFieldName);
                    }
                    else if (EQUAL(pszRawType, "string"))  // ES < 5.0
                    {
                        json_object *poRawIndex =
                            CPL_json_object_object_get(poRaw, "index");
                        if (poRawIndex && json_object_get_type(poRawIndex) ==
                                              json_type_string)
                        {
                            const char *pszRawIndex =
                                json_object_get_string(poRawIndex);
                            if (EQUAL(pszRawIndex, "not_analyzed"))
                            {
                                m_papszFieldsWithRawValue = CSLAddString(
                                    m_papszFieldsWithRawValue, osFieldName);
                            }
                        }
                    }
                }
            }
        }
    }
}

/************************************************************************/
/*                        FinalizeFeatureDefn()                         */
/************************************************************************/

void OGRElasticLayer::FinalizeFeatureDefn(bool bReadFeatures)
{
    if (m_bFeatureDefnFinalized)
        return;

    m_bFeatureDefnFinalized = true;

    int nFeatureCountToEstablishFeatureDefn =
        m_poDS->m_nFeatureCountToEstablishFeatureDefn;
    if (!m_osESSearch.empty() && nFeatureCountToEstablishFeatureDefn <= 0)
        nFeatureCountToEstablishFeatureDefn = 1;
    std::set<std::pair<CPLString, CPLString>> oVisited;

    if (bReadFeatures && nFeatureCountToEstablishFeatureDefn != 0)
    {
        // CPLDebug("ES", "Try to get %d features to establish feature
        // definition",
        //          FeatureCountToEstablishFeatureDefn);
        bool bFirst = true;
        int nAlreadyQueried = 0;
        while (true)
        {
            CPLString osRequest;
            CPLString osPostData;
            if (bFirst)
            {
                bFirst = false;
                if (!m_osESSearch.empty())
                {
                    osRequest =
                        CPLSPrintf("%s/_search?scroll=1m&size=%d",
                                   m_poDS->GetURL(), m_poDS->m_nBatchSize);
                    osPostData = m_osESSearch;
                }
                else
                {
                    osRequest = BuildMappingURL(false);
                    osRequest += CPLSPrintf("/_search?scroll=1m&size=%d",
                                            m_poDS->m_nBatchSize);
                }
            }
            else
            {
                if (m_osScrollID.empty())
                    break;
                osRequest =
                    CPLSPrintf("%s/_search/scroll?scroll=1m&scroll_id=%s",
                               m_poDS->GetURL(), m_osScrollID.c_str());
            }

            if (m_bAddPretty)
                osRequest += "&pretty";
            json_object *poResponse = m_poDS->RunRequest(osRequest, osPostData);
            if (poResponse == nullptr)
            {
                break;
            }
            json_object *poScrollID =
                CPL_json_object_object_get(poResponse, "_scroll_id");
            if (poScrollID)
            {
                const char *pszScrollID = json_object_get_string(poScrollID);
                if (pszScrollID)
                    m_osScrollID = pszScrollID;
            }

            json_object *poHits =
                json_ex_get_object_by_path(poResponse, "hits.hits");
            if (poHits == nullptr ||
                json_object_get_type(poHits) != json_type_array)
            {
                json_object_put(poResponse);
                break;
            }
            const auto nHits = json_object_array_length(poHits);
            if (nHits == 0)
            {
                m_osScrollID = "";
                json_object_put(poResponse);
                break;
            }
            for (auto i = decltype(nHits){0}; i < nHits; i++)
            {
                json_object *poHit = json_object_array_get_idx(poHits, i);
                if (poHit == nullptr ||
                    json_object_get_type(poHit) != json_type_object)
                {
                    continue;
                }
                json_object *poSource =
                    CPL_json_object_object_get(poHit, "_source");
                if (poSource == nullptr ||
                    json_object_get_type(poSource) != json_type_object)
                {
                    continue;
                }

                if (!m_osESSearch.empty())
                {
                    json_object *poIndex =
                        CPL_json_object_object_get(poHit, "_index");
                    if (poIndex == nullptr ||
                        json_object_get_type(poIndex) != json_type_string)
                        break;
                    if (m_poDS->m_nMajorVersion < 7)
                    {
                        json_object *poType =
                            CPL_json_object_object_get(poHit, "_type");
                        if (poType == nullptr ||
                            json_object_get_type(poType) != json_type_string)
                            break;
                        m_osMappingName = json_object_get_string(poType);
                    }
                    CPLString osIndex(json_object_get_string(poIndex));

                    if (oVisited.find(std::pair<CPLString, CPLString>(
                            osIndex, m_osMappingName)) == oVisited.end())
                    {
                        oVisited.insert(std::pair<CPLString, CPLString>(
                            osIndex, m_osMappingName));

                        CPLString osURL =
                            CPLSPrintf("%s/%s/_mapping", m_poDS->GetURL(),
                                       osIndex.c_str());
                        if (m_poDS->m_nMajorVersion < 7)
                            osURL += CPLSPrintf("/%s", m_osMappingName.c_str());
                        osURL += "?pretty";

                        json_object *poMappingRes = m_poDS->RunRequest(osURL);
                        if (poMappingRes)
                        {
                            json_object *poLayerObj =
                                CPL_json_object_object_get(poMappingRes,
                                                           osIndex);
                            json_object *poMappings = nullptr;
                            if (poLayerObj &&
                                json_object_get_type(poLayerObj) ==
                                    json_type_object)
                                poMappings = CPL_json_object_object_get(
                                    poLayerObj, "mappings");
                            if (poMappings &&
                                json_object_get_type(poMappings) ==
                                    json_type_object)
                            {
                                json_object *poMapping =
                                    m_poDS->m_nMajorVersion < 7
                                        ? CPL_json_object_object_get(
                                              poMappings, m_osMappingName)
                                        : poMappings;
                                if (poMapping)
                                {
                                    InitFeatureDefnFromMapping(
                                        poMapping, "",
                                        std::vector<CPLString>());
                                }
                            }
                            json_object_put(poMappingRes);
                        }
                    }
                }

                json_object_iter it;
                it.key = nullptr;
                it.val = nullptr;
                it.entry = nullptr;
                json_object_object_foreachC(poSource, it)
                {
                    if (!m_osFID.empty())
                    {
                        if (EQUAL(it.key, m_osFID))
                            continue;
                    }
                    else if (EQUAL(it.key, m_poDS->GetFID()))
                    {
                        m_osFID = it.key;
                        continue;
                    }

                    if (m_osMappingName == "FeatureCollection")
                    {
                        if (strcmp(it.key, "properties") == 0 &&
                            json_object_get_type(it.val) == json_type_object)
                        {
                            json_object_iter it2;
                            it2.key = nullptr;
                            it2.val = nullptr;
                            it2.entry = nullptr;
                            json_object_object_foreachC(it.val, it2)
                            {
                                std::vector<CPLString> aosPath;
                                aosPath.push_back("properties");
                                AddOrUpdateField(it2.key, it2.key, it2.val, '.',
                                                 aosPath);
                            }
                        }
                    }
                    else
                    {
                        std::vector<CPLString> aosPath;
                        AddOrUpdateField(it.key, it.key, it.val, '.', aosPath);
                    }
                }

                nAlreadyQueried++;
                if (nFeatureCountToEstablishFeatureDefn > 0 &&
                    nAlreadyQueried >= nFeatureCountToEstablishFeatureDefn)
                {
                    break;
                }
            }

            json_object_put(poResponse);

            if (nFeatureCountToEstablishFeatureDefn > 0 &&
                nAlreadyQueried >= nFeatureCountToEstablishFeatureDefn)
            {
                break;
            }
        }

        ResetReading();
    }

    if (m_poDS->m_bJSonField)
    {
        AddFieldDefn("_json", OFTString, std::vector<CPLString>());
    }
}

/************************************************************************/
/*                         BuildPathFromArray()                         */
/************************************************************************/

CPLString
OGRElasticLayer::BuildPathFromArray(const std::vector<CPLString> &aosPath)
{
    CPLString osPath(aosPath[0]);
    for (size_t i = 1; i < aosPath.size(); i++)
    {
        osPath += ".";
        osPath += aosPath[i];
    }
    return osPath;
}

/************************************************************************/
/*                         GetOGRGeomTypeFromES()                       */
/************************************************************************/

static OGRwkbGeometryType GetOGRGeomTypeFromES(const char *pszType)
{
    if (EQUAL(pszType, "envelope"))
        return wkbPolygon;
    if (EQUAL(pszType, "circle"))
        return wkbPolygon;
    return OGRFromOGCGeomType(pszType);
}

/************************************************************************/
/*                         AddOrUpdateField()                           */
/************************************************************************/

void OGRElasticLayer::AddOrUpdateField(const char *pszAttrName,
                                       const char *pszKey, json_object *poObj,
                                       char chNestedAttributeSeparator,
                                       std::vector<CPLString> &aosPath)
{
    json_type eJSONType = json_object_get_type(poObj);
    if (eJSONType == json_type_null)
        return;

    if (eJSONType == json_type_object)
    {
        json_object *poType = CPL_json_object_object_get(poObj, "type");
        OGRwkbGeometryType eGeomType;
        if (poType && json_object_get_type(poType) == json_type_string &&
            (eGeomType = GetOGRGeomTypeFromES(
                 json_object_get_string(poType))) != wkbUnknown &&
            CPL_json_object_object_get(
                poObj, (eGeomType == wkbGeometryCollection) ? "geometries"
                                                            : "coordinates"))
        {
            int nIndex = m_poFeatureDefn->GetGeomFieldIndex(pszAttrName);
            if (nIndex < 0)
            {
                aosPath.push_back(pszKey);
                AddGeomFieldDefn(pszAttrName, eGeomType, aosPath, FALSE);
            }
            else
            {
                OGRGeomFieldDefn *poFDefn =
                    m_poFeatureDefn->GetGeomFieldDefn(nIndex);
                if (poFDefn->GetType() != eGeomType)
                    poFDefn->SetType(wkbUnknown);
            }
        }
        else if (m_poDS->m_bFlattenNestedAttributes)
        {
            if (m_poFeatureDefn->GetGeomFieldIndex(pszAttrName) >= 0)
                return;
            aosPath.push_back(pszKey);

            json_object_iter it;
            it.key = nullptr;
            it.val = nullptr;
            it.entry = nullptr;
            json_object_object_foreachC(poObj, it)
            {
                char szSeparator[2];
                szSeparator[0] = chNestedAttributeSeparator;
                szSeparator[1] = 0;
                CPLString osAttrName(
                    CPLSPrintf("%s%s%s", pszAttrName, szSeparator, it.key));

                std::vector<CPLString> aosNewPaths(aosPath);
                AddOrUpdateField(osAttrName, it.key, it.val,
                                 chNestedAttributeSeparator, aosNewPaths);
            }
            return;
        }
    }
    /*else if( eJSONType == json_type_array )
    {
        if( m_poFeatureDefn->GetGeomFieldIndex(pszAttrName) >= 0 )
            return;
    }*/

    if (m_poFeatureDefn->GetGeomFieldIndex(pszAttrName) >= 0)
        return;

    OGRFieldSubType eNewSubType;
    OGRFieldType eNewType = GeoJSONPropertyToFieldType(poObj, eNewSubType);

    int nIndex = m_poFeatureDefn->GetFieldIndex(pszAttrName);
    OGRFieldDefn *poFDefn = nullptr;
    if (nIndex >= 0)
        poFDefn = m_poFeatureDefn->GetFieldDefn(nIndex);
    if ((poFDefn == nullptr && eNewType == OFTString) ||
        (poFDefn != nullptr &&
         (poFDefn->GetType() == OFTDate || poFDefn->GetType() == OFTDateTime ||
          poFDefn->GetType() == OFTTime)))
    {
        int nYear = 0;
        int nMonth = 0;
        int nDay = 0;
        int nHour = 0;
        int nMinute = 0;
        float fSecond = 0.0f;
        if (sscanf(json_object_get_string(poObj), "%04d/%02d/%02d %02d:%02d",
                   &nYear, &nMonth, &nDay, &nHour, &nMinute) == 5 ||
            sscanf(json_object_get_string(poObj), "%04d-%02d-%02dT%02d:%02d",
                   &nYear, &nMonth, &nDay, &nHour, &nMinute) == 5)
        {
            eNewType = OFTDateTime;
        }
        else if (sscanf(json_object_get_string(poObj), "%04d/%02d/%02d", &nYear,
                        &nMonth, &nDay) == 3 ||
                 sscanf(json_object_get_string(poObj), "%04d-%02d-%02d", &nYear,
                        &nMonth, &nDay) == 3)
        {
            eNewType = OFTDate;
        }
        else if (sscanf(json_object_get_string(poObj), "%02d:%02d:%f", &nHour,
                        &nMinute, &fSecond) == 3)
        {
            eNewType = OFTTime;
        }
    }

    if (poFDefn == nullptr)
    {
        aosPath.push_back(pszKey);
        AddFieldDefn(pszAttrName, eNewType, aosPath, eNewSubType);
    }
    else
    {
        OGRUpdateFieldType(poFDefn, eNewType, eNewSubType);
    }
}

/************************************************************************/
/*                              SyncToDisk()                            */
/************************************************************************/

OGRErr OGRElasticLayer::SyncToDisk()
{
    if (WriteMapIfNecessary() != OGRERR_NONE)
        return OGRERR_FAILURE;

    if (!PushIndex())
        return OGRERR_FAILURE;

    return OGRERR_NONE;
}

/************************************************************************/
/*                            GetLayerDefn()                            */
/************************************************************************/

const OGRFeatureDefn *OGRElasticLayer::GetLayerDefn() const
{

    const_cast<OGRElasticLayer *>(this)->FinalizeFeatureDefn();

    return m_poFeatureDefn;
}

/************************************************************************/
/*                            GetFIDColumn()                            */
/************************************************************************/

const char *OGRElasticLayer::GetFIDColumn() const
{
    GetLayerDefn();
    return m_osFID.c_str();
}

/************************************************************************/
/*                            ResetReading()                            */
/************************************************************************/

void OGRElasticLayer::ResetReading()
{
    if (!m_osScrollID.empty())
    {
        char **papszOptions =
            CSLAddNameValue(nullptr, "CUSTOMREQUEST", "DELETE");
        CPLHTTPResult *psResult = m_poDS->HTTPFetch(
            (m_poDS->GetURL() + CPLString("/_search/scroll?scroll_id=") +
             m_osScrollID)
                .c_str(),
            papszOptions);
        CSLDestroy(papszOptions);
        CPLHTTPDestroyResult(psResult);

        m_osScrollID = "";
    }
    for (int i = 0; i < (int)m_apoCachedFeatures.size(); i++)
        delete m_apoCachedFeatures[i];
    m_apoCachedFeatures.resize(0);
    m_iCurID = 0;
    m_iCurFeatureInPage = 0;
    m_bEOF = false;

    m_nReadFeaturesSinceResetReading = 0;
    m_dfEndTimeStamp = 0;
    const double dfTimeout = m_bUseSingleQueryParams
                                 ? m_dfSingleQueryTimeout
                                 : m_dfFeatureIterationTimeout;
    if (dfTimeout > 0)
        m_dfEndTimeStamp = GetTimestamp() + dfTimeout;
}

/************************************************************************/
/*                           GetNextFeature()                           */
/************************************************************************/

OGRFeature *OGRElasticLayer::GetNextFeature()

{
    FinalizeFeatureDefn();

    while (true)
    {
        OGRFeature *poFeature = GetNextRawFeature();
        if (poFeature == nullptr)
            return nullptr;

        if ((m_poFilterGeom == nullptr ||
             FilterGeometry(poFeature->GetGeomFieldRef(m_iGeomFieldFilter))) &&
            (m_poAttrQuery == nullptr || m_poAttrQuery->Evaluate(poFeature)))
            return poFeature;

        delete poFeature;
    }
}

/************************************************************************/
/*                           BuildSort()                                */
/************************************************************************/

json_object *OGRElasticLayer::BuildSort()
{
    json_object *poRet = json_object_new_array();
    for (size_t i = 0; i < m_aoSortColumns.size(); ++i)
    {
        const int nIdx =
            m_poFeatureDefn->GetFieldIndex(m_aoSortColumns[i].osColumn);
        CPLString osFieldName(nIdx == 0
                                  ? CPLString("_uid")
                                  : BuildPathFromArray(m_aaosFieldPaths[nIdx]));
        if (CSLFindString(m_papszFieldsWithRawValue,
                          m_aoSortColumns[i].osColumn) >= 0)
        {
            osFieldName += ".raw";
        }
        json_object *poSortCol = json_object_new_object();
        json_object *poSortProp = json_object_new_object();
        json_object_array_add(poRet, poSortCol);
        json_object_object_add(
            poSortProp, "order",
            json_object_new_string(m_aoSortColumns[i].bAsc ? "asc" : "desc"));
        json_object_object_add(poSortCol, osFieldName, poSortProp);
    }
    return poRet;
}

/************************************************************************/
/*                           BuildQuery()                               */
/************************************************************************/

CPLString OGRElasticLayer::BuildQuery(bool bCountOnly)
{
    CPLString osRet = "{ ";
    if (bCountOnly &&
        (m_poDS->m_nMajorVersion < 5 || !m_osSingleQueryTimeout.empty()))
    {
        osRet += "\"size\": 0, ";
    }
    if (m_poSpatialFilter && m_poJSONFilter)
    {
        osRet += CPLSPrintf("\"query\": { \"constant_score\" : { \"filter\": "
                            "{ \"bool\" : { \"must\" : [%s, %s] } } } }",
                            json_object_to_json_string(m_poSpatialFilter),
                            json_object_to_json_string(m_poJSONFilter));
    }
    else
    {
        osRet += CPLSPrintf(
            "\"query\": { \"constant_score\" : { \"filter\": %s } }",
            json_object_to_json_string(m_poSpatialFilter ? m_poSpatialFilter
                                                         : m_poJSONFilter));
    }
    if (!bCountOnly && !m_aoSortColumns.empty())
    {
        json_object *poSort = BuildSort();
        osRet +=
            CPLSPrintf(", \"sort\" : %s", json_object_to_json_string(poSort));
        json_object_put(poSort);
    }
    osRet += " }";
    return osRet;
}

/************************************************************************/
/*                         GetNextRawFeature()                          */
/************************************************************************/

OGRFeature *OGRElasticLayer::GetNextRawFeature()
{
    json_object *poResponse = nullptr;

    if (m_dfEndTimeStamp > 0 && GetTimestamp() >= m_dfEndTimeStamp)
    {
        CPLDebug("ES", "Terminating request due to timeout");
        return nullptr;
    }
    const auto nTerminateAfter = m_bUseSingleQueryParams
                                     ? m_nSingleQueryTerminateAfter
                                     : m_nFeatureIterationTerminateAfter;
    if (nTerminateAfter > 0 &&
        m_nReadFeaturesSinceResetReading >= nTerminateAfter)
    {
        CPLDebug("ES", "Terminating request due to terminate_after reached");
        return nullptr;
    }

    if (m_bEOF)
        return nullptr;

    if (m_iCurFeatureInPage < (int)m_apoCachedFeatures.size())
    {
        OGRFeature *poRet = m_apoCachedFeatures[m_iCurFeatureInPage];
        m_apoCachedFeatures[m_iCurFeatureInPage] = nullptr;
        m_iCurFeatureInPage++;
        m_nReadFeaturesSinceResetReading++;
        return poRet;
    }

    for (int i = 0; i < (int)m_apoCachedFeatures.size(); i++)
        delete m_apoCachedFeatures[i];
    m_apoCachedFeatures.resize(0);
    m_iCurFeatureInPage = 0;

    CPLString osRequest, osPostData;
    if (m_nReadFeaturesSinceResetReading == 0)
    {
        if (!m_osESSearch.empty())
        {
            osRequest = CPLSPrintf("%s/_search?scroll=1m&size=%d",
                                   m_poDS->GetURL(), m_poDS->m_nBatchSize);
            osPostData = m_osESSearch;
        }
        else if ((m_poSpatialFilter && m_osJSONFilter.empty()) ||
                 m_poJSONFilter)
        {
            osPostData = BuildQuery(false);
            osRequest = BuildMappingURL(false);
            osRequest +=
                CPLSPrintf("/_search?scroll=1m&size=%d", m_poDS->m_nBatchSize);
        }
        else if (!m_aoSortColumns.empty() && m_osJSONFilter.empty())
        {
            osRequest = BuildMappingURL(false);
            osRequest +=
                CPLSPrintf("/_search?scroll=1m&size=%d", m_poDS->m_nBatchSize);
            json_object *poSort = BuildSort();
            osPostData = CPLSPrintf("{ \"sort\": %s }",
                                    json_object_to_json_string(poSort));
            json_object_put(poSort);
        }
        else
        {
            osRequest = BuildMappingURL(false);
            osRequest +=
                CPLSPrintf("/_search?scroll=1m&size=%d", m_poDS->m_nBatchSize);
            osPostData = m_osJSONFilter;
        }
    }
    else
    {
        if (m_osScrollID.empty())
        {
            m_bEOF = true;
            return nullptr;
        }
        osRequest = CPLSPrintf("%s/_search/scroll?scroll=1m&scroll_id=%s",
                               m_poDS->GetURL(), m_osScrollID.c_str());
    }

    if (m_bAddPretty)
        osRequest += "&pretty";
    poResponse = m_poDS->RunRequest(osRequest, osPostData);
    if (poResponse == nullptr)
    {
        m_bEOF = true;
        return nullptr;
    }
    m_osScrollID.clear();
    json_object *poScrollID =
        CPL_json_object_object_get(poResponse, "_scroll_id");
    if (poScrollID)
    {
        const char *pszScrollID = json_object_get_string(poScrollID);
        if (pszScrollID)
            m_osScrollID = pszScrollID;
    }

    json_object *poHits = CPL_json_object_object_get(poResponse, "hits");
    if (poHits == nullptr || json_object_get_type(poHits) != json_type_object)
    {
        m_bEOF = true;
        json_object_put(poResponse);
        return nullptr;
    }
    poHits = CPL_json_object_object_get(poHits, "hits");
    if (poHits == nullptr || json_object_get_type(poHits) != json_type_array)
    {
        m_bEOF = true;
        json_object_put(poResponse);
        return nullptr;
    }
    const auto nHits = json_object_array_length(poHits);
    if (nHits == 0)
    {
        m_osScrollID = "";
        m_bEOF = true;
        json_object_put(poResponse);
        return nullptr;
    }
    for (auto i = decltype(nHits){0}; i < nHits; i++)
    {
        json_object *poHit = json_object_array_get_idx(poHits, i);
        if (poHit == nullptr || json_object_get_type(poHit) != json_type_object)
        {
            continue;
        }
        json_object *poSource = CPL_json_object_object_get(poHit, "_source");
        if (poSource == nullptr ||
            json_object_get_type(poSource) != json_type_object)
        {
            continue;
        }

        const char *pszId = nullptr;
        json_object *poId = CPL_json_object_object_get(poHit, "_id");
        if (poId != nullptr && json_object_get_type(poId) == json_type_string)
            pszId = json_object_get_string(poId);

        OGRFeature *poFeature = new OGRFeature(m_poFeatureDefn);
        if (pszId)
            poFeature->SetField("_id", pszId);

        if (m_bAddSourceIndexName)
        {
            json_object *poIndex = CPL_json_object_object_get(poHit, "_index");
            if (poId != nullptr &&
                json_object_get_type(poId) == json_type_string)
                poFeature->SetField("_index", json_object_get_string(poIndex));
        }

        if (!m_osESSearch.empty())
        {
            json_object *poIndex = CPL_json_object_object_get(poHit, "_index");
            if (poIndex != nullptr &&
                json_object_get_type(poIndex) == json_type_string)
                poFeature->SetField("_index", json_object_get_string(poIndex));

            json_object *poType = CPL_json_object_object_get(poHit, "_type");
            if (poType != nullptr &&
                json_object_get_type(poType) == json_type_string)
                poFeature->SetField("_type", json_object_get_string(poType));
        }

        if (m_poDS->m_bJSonField)
            poFeature->SetField("_json", json_object_to_json_string(poSource));

        BuildFeature(poFeature, poSource, CPLString());
        if (poFeature->GetFID() < 0)
            poFeature->SetFID(++m_iCurID);
        m_apoCachedFeatures.push_back(poFeature);
    }

    json_object_put(poResponse);
    if (!m_apoCachedFeatures.empty())
    {
        OGRFeature *poRet = m_apoCachedFeatures[0];
        m_apoCachedFeatures[0] = nullptr;
        m_iCurFeatureInPage++;
        m_nReadFeaturesSinceResetReading++;
        return poRet;
    }
    return nullptr;
}

/************************************************************************/
/*                      decode_geohash_bbox()                           */
/************************************************************************/

/* Derived from routine from
 * https://github.com/davetroy/geohash/blob/master/ext/geohash_native.c */
/* (c) 2008-2010 David Troy, davetroy@gmail.com, (The MIT License) */

static const char BASE32[] = "0123456789bcdefghjkmnpqrstuvwxyz";

static void decode_geohash_bbox(const char *geohash, double lat[2],
                                double lon[2])
{
    int i;
    int j;
    int hashlen;
    char c;
    char cd;
    char mask;
    char is_even = 1;
    static const char bits[] = {16, 8, 4, 2, 1};
    lat[0] = -90.0;
    lat[1] = 90.0;
    lon[0] = -180.0;
    lon[1] = 180.0;
    hashlen = static_cast<int>(strlen(geohash));
    for (i = 0; i < hashlen; i++)
    {
        c = static_cast<char>(
            CPLTolower(static_cast<unsigned char>(geohash[i])));
        cd = static_cast<char>(strchr(BASE32, c) - BASE32);
        for (j = 0; j < 5; j++)
        {
            mask = bits[j];
            if (is_even)
            {
                lon[!(cd & mask)] = (lon[0] + lon[1]) / 2;
            }
            else
            {
                lat[!(cd & mask)] = (lat[0] + lat[1]) / 2;
            }
            is_even = !is_even;
        }
    }
}

/************************************************************************/
/*                            BuildFeature()                            */
/************************************************************************/

void OGRElasticLayer::BuildFeature(OGRFeature *poFeature, json_object *poSource,
                                   CPLString osPath)
{
    json_object_iter it;
    it.key = nullptr;
    it.val = nullptr;
    it.entry = nullptr;
    CPLString osCurPath;
    json_object_object_foreachC(poSource, it)
    {
        if (osPath.empty() && !m_osFID.empty() && EQUAL(m_osFID, it.key))
        {
            json_type eJSONType = json_object_get_type(it.val);
            if (eJSONType == json_type_int)
            {
                poFeature->SetFID((GIntBig)json_object_get_int64(it.val));
                continue;
            }
        }

        if (!osPath.empty())
            osCurPath = osPath + "." + it.key;
        else
            osCurPath = it.key;
        std::map<CPLString, int>::iterator oIter =
            m_aosMapToFieldIndex.find(osCurPath);
        if (oIter != m_aosMapToFieldIndex.end())
        {
            switch (json_object_get_type(it.val))
            {
                case json_type_null:
                    poFeature->SetFieldNull(oIter->second);
                    break;
                case json_type_boolean:
                    poFeature->SetField(oIter->second,
                                        json_object_get_boolean(it.val));
                    break;
                case json_type_int:
                    poFeature->SetField(oIter->second,
                                        (GIntBig)json_object_get_int64(it.val));
                    break;
                case json_type_double:
                    poFeature->SetField(oIter->second,
                                        json_object_get_double(it.val));
                    break;
                case json_type_array:
                {
                    if (m_poFeatureDefn->GetFieldDefn(oIter->second)
                            ->GetType() == OFTIntegerList)
                    {
                        std::vector<int> anValues;
                        const auto nLength = json_object_array_length(it.val);
                        for (auto i = decltype(nLength){0}; i < nLength; i++)
                        {
                            anValues.push_back(json_object_get_int(
                                json_object_array_get_idx(it.val, i)));
                        }
                        if (nLength)
                            poFeature->SetField(oIter->second,
                                                static_cast<int>(nLength),
                                                &anValues[0]);
                    }
                    else if (m_poFeatureDefn->GetFieldDefn(oIter->second)
                                 ->GetType() == OFTInteger64List)
                    {
                        std::vector<GIntBig> anValues;
                        const auto nLength = json_object_array_length(it.val);
                        for (auto i = decltype(nLength){0}; i < nLength; i++)
                        {
                            anValues.push_back(json_object_get_int64(
                                json_object_array_get_idx(it.val, i)));
                        }
                        if (nLength)
                            poFeature->SetField(oIter->second,
                                                static_cast<int>(nLength),
                                                &anValues[0]);
                    }
                    else if (m_poFeatureDefn->GetFieldDefn(oIter->second)
                                 ->GetType() == OFTRealList)
                    {
                        std::vector<double> adfValues;
                        const auto nLength = json_object_array_length(it.val);
                        for (auto i = decltype(nLength){0}; i < nLength; i++)
                        {
                            adfValues.push_back(json_object_get_double(
                                json_object_array_get_idx(it.val, i)));
                        }
                        if (nLength)
                            poFeature->SetField(oIter->second,
                                                static_cast<int>(nLength),
                                                &adfValues[0]);
                    }
                    else if (m_poFeatureDefn->GetFieldDefn(oIter->second)
                                 ->GetType() == OFTStringList)
                    {
                        std::vector<char *> apszValues;
                        const auto nLength = json_object_array_length(it.val);
                        for (auto i = decltype(nLength){0}; i < nLength; i++)
                        {
                            apszValues.push_back(
                                CPLStrdup(json_object_get_string(
                                    json_object_array_get_idx(it.val, i))));
                        }
                        apszValues.push_back(nullptr);
                        poFeature->SetField(oIter->second, &apszValues[0]);
                        for (auto i = decltype(nLength){0}; i < nLength; i++)
                        {
                            CPLFree(apszValues[i]);
                        }
                    }
                    break;
                }
                default:
                {
                    if (m_poFeatureDefn->GetFieldDefn(oIter->second)
                            ->GetType() == OFTBinary)
                    {
                        GByte *pabyBase64 =
                            (GByte *)CPLStrdup(json_object_get_string(it.val));
                        int nBytes = CPLBase64DecodeInPlace(pabyBase64);
                        poFeature->SetField(oIter->second, nBytes, pabyBase64);
                        CPLFree(pabyBase64);
                    }
                    else
                    {
                        poFeature->SetField(oIter->second,
                                            json_object_get_string(it.val));
                    }
                    break;
                }
            }
        }
        else if ((oIter = m_aosMapToGeomFieldIndex.find(osCurPath)) !=
                 m_aosMapToGeomFieldIndex.end())
        {
            const auto poSRS = m_poFeatureDefn->GetGeomFieldDefn(oIter->second)
                                   ->GetSpatialRef();
            OGRGeometry *poGeom = nullptr;
            if (m_abIsGeoPoint[oIter->second])
            {
                json_type eJSONType = json_object_get_type(it.val);
                if (eJSONType == json_type_array &&
                    json_object_array_length(it.val) == 2)
                {
                    json_object *poX = json_object_array_get_idx(it.val, 0);
                    json_object *poY = json_object_array_get_idx(it.val, 1);
                    if (poX != nullptr && poY != nullptr)
                    {
                        poGeom = new OGRPoint(json_object_get_double(poX),
                                              json_object_get_double(poY));
                    }
                }
                else if (eJSONType == json_type_object)
                {
                    json_object *poX =
                        CPL_json_object_object_get(it.val, "lon");
                    json_object *poY =
                        CPL_json_object_object_get(it.val, "lat");
                    if (poX != nullptr && poY != nullptr)
                    {
                        poGeom = new OGRPoint(json_object_get_double(poX),
                                              json_object_get_double(poY));
                    }
                }
                else if (eJSONType == json_type_string)
                {
                    const char *pszLatLon = json_object_get_string(it.val);
                    char **papszTokens = CSLTokenizeString2(pszLatLon, ",", 0);
                    if (CSLCount(papszTokens) == 2)
                    {
                        poGeom = new OGRPoint(CPLAtof(papszTokens[1]),
                                              CPLAtof(papszTokens[0]));
                    }
                    else
                    {
                        double lat[2] = {0.0, 0.0};
                        double lon[2] = {0.0, 0.0};
                        decode_geohash_bbox(pszLatLon, lat, lon);
                        poGeom = new OGRPoint((lon[0] + lon[1]) / 2,
                                              (lat[0] + lat[1]) / 2);
                    }

                    CSLDestroy(papszTokens);
                }
            }
            else if (json_object_get_type(it.val) == json_type_object)
            {
                json_object *poType =
                    CPL_json_object_object_get(it.val, "type");
                json_object *poRadius =
                    CPL_json_object_object_get(it.val, "radius");
                json_object *poCoordinates =
                    CPL_json_object_object_get(it.val, "coordinates");
                if (poType && poRadius && poCoordinates &&
                    json_object_get_type(poType) == json_type_string &&
                    EQUAL(json_object_get_string(poType), "circle") &&
                    (json_object_get_type(poRadius) == json_type_string ||
                     json_object_get_type(poRadius) == json_type_double ||
                     json_object_get_type(poRadius) == json_type_int) &&
                    json_object_get_type(poCoordinates) == json_type_array &&
                    json_object_array_length(poCoordinates) == 2)
                {
                    const char *pszRadius = json_object_get_string(poRadius);
                    const double dfX = json_object_get_double(
                        json_object_array_get_idx(poCoordinates, 0));
                    const double dfY = json_object_get_double(
                        json_object_array_get_idx(poCoordinates, 1));
                    const int nRadiusLength = (int)strlen(pszRadius);
                    double dfRadius = CPLAtof(pszRadius);
                    double dfUnit = 0.0;
                    if (nRadiusLength >= 1 &&
                        pszRadius[nRadiusLength - 1] == 'm')
                    {
                        if (nRadiusLength >= 2 &&
                            pszRadius[nRadiusLength - 2] == 'k')
                            dfUnit = 1000;
                        else if (nRadiusLength >= 2 &&
                                 pszRadius[nRadiusLength - 2] >= '0' &&
                                 pszRadius[nRadiusLength - 2] <= '9')
                            dfUnit = 1;
                    }
                    else if (nRadiusLength >= 1 &&
                             pszRadius[nRadiusLength - 1] >= '0' &&
                             pszRadius[nRadiusLength - 1] <= '9')
                    {
                        dfUnit = 1;
                    }

                    if (dfRadius == 0)
                        CPLError(CE_Warning, CPLE_AppDefined,
                                 "Unknown unit in %s", pszRadius);
                    else
                    {
                        dfRadius *= dfUnit;
                        OGRLinearRing *poRing = new OGRLinearRing();
                        double dfSemiMajor = OGR_GREATCIRCLE_DEFAULT_RADIUS;
                        if (poSRS && poSRS->IsGeographic())
                            dfSemiMajor = poSRS->GetSemiMajor();
                        for (double dfStep = 0; dfStep <= 360; dfStep += 4)
                        {
                            double dfLat = 0.0;
                            double dfLon = 0.0;
                            OGR_GreatCircle_ExtendPosition(dfY, dfX, dfRadius,
                                                           dfSemiMajor, dfStep,
                                                           &dfLat, &dfLon);
                            poRing->addPoint(dfLon, dfLat);
                        }
                        OGRPolygon *poPoly = new OGRPolygon();
                        poPoly->addRingDirectly(poRing);
                        poGeom = poPoly;
                    }
                }
                else if (poType && poCoordinates &&
                         json_object_get_type(poType) == json_type_string &&
                         EQUAL(json_object_get_string(poType), "envelope") &&
                         json_object_get_type(poCoordinates) ==
                             json_type_array &&
                         json_object_array_length(poCoordinates) == 2)
                {
                    json_object *poCorner1 =
                        json_object_array_get_idx(poCoordinates, 0);
                    json_object *poCorner2 =
                        json_object_array_get_idx(poCoordinates, 1);
                    if (poCorner1 && poCorner2 &&
                        json_object_get_type(poCorner1) == json_type_array &&
                        json_object_array_length(poCorner1) == 2 &&
                        json_object_get_type(poCorner2) == json_type_array &&
                        json_object_array_length(poCorner2) == 2)
                    {
                        const double dfX1 = json_object_get_double(
                            json_object_array_get_idx(poCorner1, 0));
                        const double dfY1 = json_object_get_double(
                            json_object_array_get_idx(poCorner1, 1));
                        const double dfX2 = json_object_get_double(
                            json_object_array_get_idx(poCorner2, 0));
                        const double dfY2 = json_object_get_double(
                            json_object_array_get_idx(poCorner2, 1));
                        OGRLinearRing *poRing = new OGRLinearRing();
                        poRing->addPoint(dfX1, dfY1);
                        poRing->addPoint(dfX2, dfY1);
                        poRing->addPoint(dfX2, dfY2);
                        poRing->addPoint(dfX1, dfY2);
                        poRing->addPoint(dfX1, dfY1);
                        OGRPolygon *poPoly = new OGRPolygon();
                        poPoly->addRingDirectly(poRing);
                        poGeom = poPoly;
                    }
                }
                else
                {
                    poGeom = OGRGeoJSONReadGeometry(
                                 it.val, /* bHasM = */ false,
                                 /* OGRSpatialReference* = */ nullptr)
                                 .release();
                }
            }
            else if (json_object_get_type(it.val) == json_type_string)
            {
                // Assume this is WKT
                OGRGeometryFactory::createFromWkt(
                    json_object_get_string(it.val), nullptr, &poGeom);
            }

            if (poGeom != nullptr)
            {
                poGeom->assignSpatialReference(poSRS);
                poFeature->SetGeomFieldDirectly(oIter->second, poGeom);
            }
        }
        else if (json_object_get_type(it.val) == json_type_object &&
                 (m_poDS->m_bFlattenNestedAttributes ||
                  (osPath.empty() && m_osMappingName == "FeatureCollection" &&
                   strcmp(it.key, "properties") == 0)))
        {
            BuildFeature(poFeature, it.val, osCurPath);
        }
        else if (json_object_get_type(it.val) == json_type_object &&
                 !m_poDS->m_bFlattenNestedAttributes)
        {
            if (m_aosMapToGeomFieldIndex.find(osCurPath + ".coordinates") !=
                m_aosMapToGeomFieldIndex.end())
            {
                BuildFeature(poFeature, it.val, osCurPath);
            }
        }
    }
}

/************************************************************************/
/*                            AppendGroup()                             */
/************************************************************************/

static json_object *AppendGroup(json_object *parent, const CPLString &name)
{
    json_object *obj = json_object_new_object();
    json_object *properties = json_object_new_object();
    json_object_object_add(parent, name, obj);
    json_object_object_add(obj, "properties", properties);
    return properties;
}

/************************************************************************/
/*                           AddPropertyMap()                           */
/************************************************************************/

static json_object *AddPropertyMap(const CPLString &type)
{
    json_object *obj = json_object_new_object();
    json_object_object_add(obj, "type", json_object_new_string(type.c_str()));
    return obj;
}

/************************************************************************/
/*                      GetContainerForMapping()                        */
/************************************************************************/

static json_object *
GetContainerForMapping(json_object *poContainer,
                       const std::vector<CPLString> &aosPath,
                       std::map<std::vector<CPLString>, json_object *> &oMap)
{
    std::vector<CPLString> aosSubPath;
    for (int j = 0; j < (int)aosPath.size() - 1; j++)
    {
        aosSubPath.push_back(aosPath[j]);
        std::map<std::vector<CPLString>, json_object *>::iterator oIter =
            oMap.find(aosSubPath);
        if (oIter == oMap.end())
        {
            json_object *poNewContainer = json_object_new_object();
            json_object *poProperties = json_object_new_object();
            json_object_object_add(poContainer, aosPath[j], poNewContainer);
            json_object_object_add(poNewContainer, "properties", poProperties);
            oMap[aosSubPath] = poProperties;
            poContainer = poProperties;
        }
        else
        {
            poContainer = oIter->second;
        }
    }
    return poContainer;
}

/************************************************************************/
/*                             BuildMap()                               */
/************************************************************************/

CPLString OGRElasticLayer::BuildMap()
{
    json_object *map = json_object_new_object();

    std::map<std::vector<CPLString>, json_object *> oMap;

    json_object *poMapping;
    json_object *poMappingProperties = json_object_new_object();
    if (m_poDS->m_nMajorVersion < 7)
    {
        poMapping = json_object_new_object();
        json_object_object_add(map, m_osMappingName, poMapping);
    }
    else
    {
        poMapping = map;
    }
    json_object_object_add(poMapping, "properties", poMappingProperties);

    if (m_poDS->m_nMajorVersion < 7 && m_osMappingName == "FeatureCollection")
    {
        json_object_object_add(
            poMappingProperties, "type",
            AddPropertyMap(m_poDS->m_nMajorVersion >= 5 ? "text" : "string"));

        std::vector<CPLString> aosPath;
        aosPath.push_back("properties");
        aosPath.push_back("dummy");
        GetContainerForMapping(poMappingProperties, aosPath, oMap);
    }

    /* skip _id field */
    for (int i = 1; i < m_poFeatureDefn->GetFieldCount(); i++)
    {
        OGRFieldDefn *poFieldDefn = m_poFeatureDefn->GetFieldDefn(i);

        json_object *poContainer = GetContainerForMapping(
            poMappingProperties, m_aaosFieldPaths[i], oMap);
        const char *pszLastComponent = m_aaosFieldPaths[i].back();

        const char *pszType = "string";
        const char *pszFormat = nullptr;

        switch (poFieldDefn->GetType())
        {
            case OFTInteger:
            case OFTIntegerList:
            {
                if (poFieldDefn->GetSubType() == OFSTBoolean)
                    pszType = "boolean";
                else
                    pszType = "integer";
                break;
            }
            case OFTInteger64:
            case OFTInteger64List:
                pszType = "long";
                break;
            case OFTReal:
            case OFTRealList:
                pszType = "double";
                break;
            case OFTDateTime:
            case OFTDate:
                pszType = "date";
                pszFormat = "yyyy/MM/dd HH:mm:ss.SSSZZ||yyyy/MM/dd "
                            "HH:mm:ss.SSS||yyyy/MM/dd";
                break;
            case OFTTime:
                pszType = "date";
                pszFormat = "HH:mm:ss.SSS";
                break;
            case OFTBinary:
                pszType = "binary";
                break;
            default:
                break;
        }

        bool bAnalyzed = EQUAL(pszType, "string");
        json_object *poPropertyMap = json_object_new_object();
        if (m_poDS->m_nMajorVersion >= 5 && EQUAL(pszType, "string"))
        {
            if (CSLFindString(m_papszNotAnalyzedFields,
                              poFieldDefn->GetNameRef()) >= 0 ||
                (CSLCount(m_papszNotAnalyzedFields) == 1 &&
                 EQUAL(m_papszNotAnalyzedFields[0], "{ALL}")))
            {
                bAnalyzed = false;
                pszType = "keyword";
            }
            else
                pszType = "text";
        }
        json_object_object_add(poPropertyMap, "type",
                               json_object_new_string(pszType));
        if (pszFormat)
            json_object_object_add(poPropertyMap, "format",
                                   json_object_new_string(pszFormat));
        if (m_bStoreFields ||
            CSLFindString(m_papszStoredFields, poFieldDefn->GetNameRef()) >= 0)
            json_object_object_add(poPropertyMap, "store",
                                   json_object_new_string("yes"));
        if (m_poDS->m_nMajorVersion < 5 &&
            (CSLFindString(m_papszNotAnalyzedFields,
                           poFieldDefn->GetNameRef()) >= 0 ||
             (CSLCount(m_papszNotAnalyzedFields) == 1 &&
              EQUAL(m_papszNotAnalyzedFields[0], "{ALL}"))))
        {
            bAnalyzed = false;
            json_object_object_add(poPropertyMap, "index",
                                   json_object_new_string("not_analyzed"));
        }
        else if (CSLFindString(m_papszNotIndexedFields,
                               poFieldDefn->GetNameRef()) >= 0)
            json_object_object_add(poPropertyMap, "index",
                                   json_object_new_string("no"));

        if (bAnalyzed && (CSLFindString(m_papszFieldsWithRawValue,
                                        poFieldDefn->GetNameRef()) >= 0 ||
                          (CSLCount(m_papszFieldsWithRawValue) == 1 &&
                           EQUAL(m_papszFieldsWithRawValue[0], "{ALL}"))))
        {
            json_object *poFields = json_object_new_object();
            json_object *poRaw = json_object_new_object();
            json_object_object_add(poFields, "raw", poRaw);
            if (m_poDS->m_nMajorVersion >= 5)
            {
                json_object_object_add(poRaw, "type",
                                       json_object_new_string("keyword"));
            }
            else
            {
                json_object_object_add(poRaw, "type",
                                       json_object_new_string("string"));
                json_object_object_add(poRaw, "index",
                                       json_object_new_string("not_analyzed"));
            }
            json_object_object_add(poPropertyMap, "fields", poFields);
        }

        json_object_object_add(poContainer, pszLastComponent, poPropertyMap);
    }

    for (int i = 0; i < m_poFeatureDefn->GetGeomFieldCount(); i++)
    {
        std::vector<CPLString> aosPath = m_aaosGeomFieldPaths[i];
        bool bAddGeoJSONType = false;
        if (m_abIsGeoPoint[i] && aosPath.size() >= 2 &&
            aosPath.back() == "coordinates")
        {
            bAddGeoJSONType = true;
            aosPath.resize((int)aosPath.size() - 1);
        }

        json_object *poContainer =
            GetContainerForMapping(poMappingProperties, aosPath, oMap);
        const char *pszLastComponent = aosPath.back();

        if (m_abIsGeoPoint[i])
        {
            json_object *geo_point = AddPropertyMap("geo_point");
            if (bAddGeoJSONType)
            {
                json_object *geometry =
                    AppendGroup(poContainer, pszLastComponent);
                json_object_object_add(
                    geometry, "type",
                    AddPropertyMap(m_poDS->m_nMajorVersion >= 5 ? "text"
                                                                : "string"));
                json_object_object_add(geometry, "coordinates", geo_point);
            }
            else
            {
                json_object_object_add(poContainer, pszLastComponent,
                                       geo_point);
            }
            if (!m_osPrecision.empty())
            {
                json_object *field_data = json_object_new_object();
                json_object_object_add(geo_point, "fielddata", field_data);
                json_object_object_add(field_data, "format",
                                       json_object_new_string("compressed"));
                json_object_object_add(
                    field_data, "precision",
                    json_object_new_string(m_osPrecision.c_str()));
            }
        }
        else
        {
            json_object *geometry = json_object_new_object();
            json_object_object_add(poContainer, pszLastComponent, geometry);
            json_object_object_add(geometry, "type",
                                   json_object_new_string("geo_shape"));
            if (!m_osPrecision.empty())
                json_object_object_add(
                    geometry, "precision",
                    json_object_new_string(m_osPrecision.c_str()));
        }
    }

    json_object *poMeta = nullptr;
    json_object *poGeomFields = nullptr;
    json_object *poFields = nullptr;
    if (!m_osFID.empty())
    {
        poMeta = json_object_new_object();
        json_object_object_add(poMeta, "fid",
                               json_object_new_string(m_osFID.c_str()));
    }
    for (int i = 0; i < m_poFeatureDefn->GetGeomFieldCount(); i++)
    {
        OGRGeomFieldDefn *poGeomFieldDefn =
            m_poFeatureDefn->GetGeomFieldDefn(i);
        if (!m_abIsGeoPoint[i] && poGeomFieldDefn->GetType() != wkbUnknown)
        {
            if (poMeta == nullptr)
                poMeta = json_object_new_object();
            if (poGeomFields == nullptr)
            {
                poGeomFields = json_object_new_object();
                json_object_object_add(poMeta, "geomfields", poGeomFields);
            }
            json_object_object_add(poGeomFields, poGeomFieldDefn->GetNameRef(),
                                   json_object_new_string(OGRToOGCGeomType(
                                       poGeomFieldDefn->GetType())));
        }
    }
    for (int i = 0; i < m_poFeatureDefn->GetFieldCount(); i++)
    {
        OGRFieldDefn *poFieldDefn = m_poFeatureDefn->GetFieldDefn(i);
        OGRFieldType eType = poFieldDefn->GetType();
        if (eType == OFTIntegerList || eType == OFTInteger64List ||
            eType == OFTRealList || eType == OFTStringList)
        {
            if (poMeta == nullptr)
                poMeta = json_object_new_object();
            if (poFields == nullptr)
            {
                poFields = json_object_new_object();
                json_object_object_add(poMeta, "fields", poFields);
            }
            json_object_object_add(
                poFields, poFieldDefn->GetNameRef(),
                json_object_new_string(OGR_GetFieldTypeName(eType)));
        }
    }
    if (poMeta)
        json_object_object_add(poMapping, "_meta", poMeta);

    CPLString jsonMap(json_object_to_json_string(map));
    json_object_put(map);

    // Got personally caught by that...
    if (CSLCount(m_papszStoredFields) == 1 &&
        (EQUAL(m_papszStoredFields[0], "YES") ||
         EQUAL(m_papszStoredFields[0], "TRUE")) &&
        m_poFeatureDefn->GetFieldIndex(m_papszStoredFields[0]) < 0)
    {
        CPLError(CE_Warning, CPLE_AppDefined,
                 "STORED_FIELDS=%s was specified. Perhaps you meant "
                 "STORE_FIELDS=%s instead?",
                 m_papszStoredFields[0], m_papszStoredFields[0]);
    }

    return jsonMap;
}

/************************************************************************/
/*                       BuildGeoJSONGeometry()                         */
/************************************************************************/

static void BuildGeoJSONGeometry(json_object *geometry,
                                 const OGRGeometry *poGeom)
{
    const int nPrecision = 10;
    double dfEps = pow(10.0, -(double)nPrecision);
    const char *pszGeomType = "";
    switch (wkbFlatten(poGeom->getGeometryType()))
    {
        case wkbPoint:
            pszGeomType = "point";
            break;
        case wkbLineString:
            pszGeomType = "linestring";
            break;
        case wkbPolygon:
            pszGeomType = "polygon";
            break;
        case wkbMultiPoint:
            pszGeomType = "multipoint";
            break;
        case wkbMultiLineString:
            pszGeomType = "multilinestring";
            break;
        case wkbMultiPolygon:
            pszGeomType = "multipolygon";
            break;
        case wkbGeometryCollection:
            pszGeomType = "geometrycollection";
            break;
        default:
            break;
    }
    json_object_object_add(geometry, "type",
                           json_object_new_string(pszGeomType));

    switch (wkbFlatten(poGeom->getGeometryType()))
    {
        case wkbPoint:
        {
            const OGRPoint *poPoint = poGeom->toPoint();
            json_object *coordinates = json_object_new_array();
            json_object_object_add(geometry, "coordinates", coordinates);
            json_object_array_add(coordinates,
                                  json_object_new_double_with_precision(
                                      poPoint->getX(), nPrecision));
            json_object_array_add(coordinates,
                                  json_object_new_double_with_precision(
                                      poPoint->getY(), nPrecision));
            break;
        }

        case wkbLineString:
        {
            const OGRLineString *poLS = poGeom->toLineString();
            json_object *coordinates = json_object_new_array();
            json_object_object_add(geometry, "coordinates", coordinates);
            for (int i = 0; i < poLS->getNumPoints(); i++)
            {
                json_object *point = json_object_new_array();
                json_object_array_add(coordinates, point);
                json_object_array_add(
                    point, json_object_new_double_with_precision(poLS->getX(i),
                                                                 nPrecision));
                json_object_array_add(
                    point, json_object_new_double_with_precision(poLS->getY(i),
                                                                 nPrecision));
            }
            break;
        }

        case wkbPolygon:
        {
            const OGRPolygon *poPoly = poGeom->toPolygon();
            json_object *coordinates = json_object_new_array();
            json_object_object_add(geometry, "coordinates", coordinates);
            for (auto &&poLS : *poPoly)
            {
                json_object *ring = json_object_new_array();
                json_object_array_add(coordinates, ring);
                for (int j = 0; j < poLS->getNumPoints(); j++)
                {
                    if (j > 0 &&
                        fabs(poLS->getX(j) - poLS->getX(j - 1)) < dfEps &&
                        fabs(poLS->getY(j) - poLS->getY(j - 1)) < dfEps)
                        continue;
                    json_object *point = json_object_new_array();
                    json_object_array_add(ring, point);
                    json_object_array_add(point,
                                          json_object_new_double_with_precision(
                                              poLS->getX(j), nPrecision));
                    json_object_array_add(point,
                                          json_object_new_double_with_precision(
                                              poLS->getY(j), nPrecision));
                }
            }
            break;
        }

        case wkbMultiPoint:
        {
            const OGRMultiPoint *poMP = poGeom->toMultiPoint();
            json_object *coordinates = json_object_new_array();
            json_object_object_add(geometry, "coordinates", coordinates);
            for (auto &&poPoint : *poMP)
            {
                json_object *point = json_object_new_array();
                json_object_array_add(coordinates, point);
                json_object_array_add(point,
                                      json_object_new_double_with_precision(
                                          poPoint->getX(), nPrecision));
                json_object_array_add(point,
                                      json_object_new_double_with_precision(
                                          poPoint->getY(), nPrecision));
            }
            break;
        }

        case wkbMultiLineString:
        {
            const OGRMultiLineString *poMLS = poGeom->toMultiLineString();
            json_object *coordinates = json_object_new_array();
            json_object_object_add(geometry, "coordinates", coordinates);
            for (auto &&poLS : *poMLS)
            {
                json_object *ls = json_object_new_array();
                json_object_array_add(coordinates, ls);
                for (auto &&oPoint : *poLS)
                {
                    json_object *point = json_object_new_array();
                    json_object_array_add(ls, point);
                    json_object_array_add(point,
                                          json_object_new_double_with_precision(
                                              oPoint.getX(), nPrecision));
                    json_object_array_add(point,
                                          json_object_new_double_with_precision(
                                              oPoint.getY(), nPrecision));
                }
            }
            break;
        }

        case wkbMultiPolygon:
        {
            const OGRMultiPolygon *poMP = poGeom->toMultiPolygon();
            json_object *coordinates = json_object_new_array();
            json_object_object_add(geometry, "coordinates", coordinates);
            for (auto &&poPoly : *poMP)
            {
                json_object *poly = json_object_new_array();
                json_object_array_add(coordinates, poly);
                for (auto &&poLS : *poPoly)
                {
                    json_object *ring = json_object_new_array();
                    json_object_array_add(poly, ring);
                    for (int k = 0; k < poLS->getNumPoints(); k++)
                    {
                        if (k > 0 &&
                            fabs(poLS->getX(k) - poLS->getX(k - 1)) < dfEps &&
                            fabs(poLS->getY(k) - poLS->getY(k - 1)) < dfEps)
                            continue;
                        json_object *point = json_object_new_array();
                        json_object_array_add(ring, point);
                        json_object_array_add(
                            point, json_object_new_double_with_precision(
                                       poLS->getX(k), nPrecision));
                        json_object_array_add(
                            point, json_object_new_double_with_precision(
                                       poLS->getY(k), nPrecision));
                    }
                }
            }
            break;
        }

        case wkbGeometryCollection:
        {
            const OGRGeometryCollection *poGC = poGeom->toGeometryCollection();
            json_object *geometries = json_object_new_array();
            json_object_object_add(geometry, "geometries", geometries);
            for (auto &&poSubGeom : *poGC)
            {
                json_object *subgeom = json_object_new_object();
                json_object_array_add(geometries, subgeom);
                BuildGeoJSONGeometry(subgeom, poSubGeom);
            }
            break;
        }

        default:
            break;
    }
}

/************************************************************************/
/*                       WriteMapIfNecessary()                          */
/************************************************************************/

OGRErr OGRElasticLayer::WriteMapIfNecessary()
{
    if (m_bManualMapping)
        return OGRERR_NONE;

    // Check to see if the user has elected to only write out the mapping file
    // This method will only write out one layer from the vector file in cases
    // where there are multiple layers
    if (!m_osWriteMapFilename.empty())
    {
        if (m_bSerializeMapping)
        {
            m_bSerializeMapping = false;
            CPLString map = BuildMap();

            // Write the map to a file
            VSILFILE *f = VSIFOpenL(m_osWriteMapFilename, "wb");
            if (f)
            {
                VSIFWriteL(map.c_str(), 1, map.length(), f);
                VSIFCloseL(f);
            }
        }
        return OGRERR_NONE;
    }

    // Check to see if we have any fields to upload to this index
    if (m_osWriteMapFilename.empty() && m_bSerializeMapping)
    {
        m_bSerializeMapping = false;
        CPLString osURL = BuildMappingURL(true);
        if (!m_poDS->UploadFile(osURL.c_str(), BuildMap()))
        {
            return OGRERR_FAILURE;
        }
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                      GetContainerForFeature()                        */
/************************************************************************/

static json_object *
GetContainerForFeature(json_object *poContainer,
                       const std::vector<CPLString> &aosPath,
                       std::map<std::vector<CPLString>, json_object *> &oMap)
{
    std::vector<CPLString> aosSubPath;
    for (int j = 0; j < (int)aosPath.size() - 1; j++)
    {
        aosSubPath.push_back(aosPath[j]);
        std::map<std::vector<CPLString>, json_object *>::iterator oIter =
            oMap.find(aosSubPath);
        if (oIter == oMap.end())
        {
            json_object *poNewContainer = json_object_new_object();
            json_object_object_add(poContainer, aosPath[j], poNewContainer);
            oMap[aosSubPath] = poNewContainer;
            poContainer = poNewContainer;
        }
        else
        {
            poContainer = oIter->second;
        }
    }
    return poContainer;
}

/************************************************************************/
/*                        BuildMappingURL()                             */
/************************************************************************/
CPLString OGRElasticLayer::BuildMappingURL(bool bMappingApi)
{
    CPLString osURL =
        CPLSPrintf("%s/%s", m_poDS->GetURL(), m_osIndexName.c_str());
    if (bMappingApi)
        osURL += "/_mapping";
    if (m_poDS->m_nMajorVersion < 7)
        osURL += CPLSPrintf("/%s", m_osMappingName.c_str());
    return osURL;
}

/************************************************************************/
/*                        BuildJSonFromFeature()                        */
/************************************************************************/

CPLString OGRElasticLayer::BuildJSonFromFeature(OGRFeature *poFeature)
{

    CPLString fields;
    int nJSonFieldIndex = m_poFeatureDefn->GetFieldIndex("_json");
    if (nJSonFieldIndex >= 0 &&
        poFeature->IsFieldSetAndNotNull(nJSonFieldIndex))
    {
        fields = poFeature->GetFieldAsString(nJSonFieldIndex);
    }
    else
    {
        json_object *fieldObject = json_object_new_object();

        if (poFeature->GetFID() >= 0 && !m_osFID.empty())
        {
            json_object_object_add(fieldObject, m_osFID.c_str(),
                                   json_object_new_int64(poFeature->GetFID()));
        }

        std::map<std::vector<CPLString>, json_object *> oMap;

        for (int i = 0; i < poFeature->GetGeomFieldCount(); i++)
        {
            OGRGeometry *poGeom = poFeature->GetGeomFieldRef(i);
            if (poGeom != nullptr && !poGeom->IsEmpty())
            {
                OGREnvelope env;
                poGeom->getEnvelope(&env);

                if (m_apoCT[i] != nullptr)
                    poGeom->transform(m_apoCT[i]);
                else if (env.MinX < -180 || env.MinY < -90 || env.MaxX > 180 ||
                         env.MaxY > 90)
                {
                    CPLErrorOnce(
                        CE_Warning, CPLE_AppDefined,
                        "At least one geometry has a bounding box outside "
                        "of [-180,180] longitude range and/or [-90,90] "
                        "latitude range. Undefined behavior");
                }

                std::vector<CPLString> aosPath = m_aaosGeomFieldPaths[i];
                bool bAddGeoJSONType = false;
                if (m_abIsGeoPoint[i] && aosPath.size() >= 2 &&
                    aosPath.back() == "coordinates")
                {
                    bAddGeoJSONType = true;
                    aosPath.resize((int)aosPath.size() - 1);
                }

                json_object *poContainer =
                    GetContainerForFeature(fieldObject, aosPath, oMap);
                const char *pszLastComponent = aosPath.back();

                if (m_abIsGeoPoint[i])
                {
                    json_object *coordinates = json_object_new_array();
                    const int nPrecision = 10;
                    json_object_array_add(
                        coordinates,
                        json_object_new_double_with_precision(
                            (env.MaxX + env.MinX) * 0.5, nPrecision));
                    json_object_array_add(
                        coordinates,
                        json_object_new_double_with_precision(
                            (env.MaxY + env.MinY) * 0.5, nPrecision));

                    if (bAddGeoJSONType)
                    {
                        json_object *geometry = json_object_new_object();
                        json_object_object_add(poContainer, pszLastComponent,
                                               geometry);
                        json_object_object_add(geometry, "type",
                                               json_object_new_string("Point"));
                        json_object_object_add(geometry, "coordinates",
                                               coordinates);
                    }
                    else
                    {
                        json_object_object_add(poContainer, pszLastComponent,
                                               coordinates);
                    }
                }
                else
                {
                    if (m_bGeoShapeAsGeoJSON)
                    {
                        json_object *geometry = json_object_new_object();
                        json_object_object_add(poContainer, pszLastComponent,
                                               geometry);
                        BuildGeoJSONGeometry(geometry, poGeom);
                    }
                    else
                    {
                        char *pszWKT = nullptr;
                        poGeom->exportToWkt(&pszWKT);
                        json_object_object_add(poContainer, pszLastComponent,
                                               json_object_new_string(pszWKT));
                        CPLFree(pszWKT);
                    }
                }
            }
        }

        if (m_osMappingName == "FeatureCollection")
        {
            if (poFeature->GetGeomFieldCount() == 1 &&
                poFeature->GetGeomFieldRef(0))
            {
                json_object_object_add(fieldObject, "type",
                                       json_object_new_string("Feature"));
            }

            std::vector<CPLString> aosPath;
            aosPath.push_back("properties");
            aosPath.push_back("dummy");
            GetContainerForFeature(fieldObject, aosPath, oMap);
        }

        // For every field (except _id)
        int fieldCount = m_poFeatureDefn->GetFieldCount();
        for (int i = 1; i < fieldCount; i++)
        {
            if (!poFeature->IsFieldSet(i))
            {
                continue;
            }

            json_object *poContainer =
                GetContainerForFeature(fieldObject, m_aaosFieldPaths[i], oMap);
            const char *pszLastComponent = m_aaosFieldPaths[i].back();

            if (poFeature->IsFieldNull(i))
            {
                json_object_object_add(poContainer, pszLastComponent, nullptr);
                continue;
            }

            switch (m_poFeatureDefn->GetFieldDefn(i)->GetType())
            {
                case OFTInteger:
                    if (m_poFeatureDefn->GetFieldDefn(i)->GetSubType() ==
                        OFSTBoolean)
                        json_object_object_add(
                            poContainer, pszLastComponent,
                            json_object_new_boolean(
                                poFeature->GetFieldAsInteger(i)));
                    else
                        json_object_object_add(
                            poContainer, pszLastComponent,
                            json_object_new_int(
                                poFeature->GetFieldAsInteger(i)));
                    break;
                case OFTInteger64:
                    json_object_object_add(
                        poContainer, pszLastComponent,
                        json_object_new_int64(
                            poFeature->GetFieldAsInteger64(i)));
                    break;
                case OFTReal:
                    json_object_object_add(
                        poContainer, pszLastComponent,
                        json_object_new_double_with_significant_figures(
                            poFeature->GetFieldAsDouble(i), -1));
                    break;
                case OFTIntegerList:
                {
                    int nCount = 0;
                    const int *panValues =
                        poFeature->GetFieldAsIntegerList(i, &nCount);
                    json_object *poArray = json_object_new_array();
                    for (int j = 0; j < nCount; j++)
                        json_object_array_add(
                            poArray, json_object_new_int(panValues[j]));
                    json_object_object_add(poContainer, pszLastComponent,
                                           poArray);
                    break;
                }
                case OFTInteger64List:
                {
                    int nCount = 0;
                    const GIntBig *panValues =
                        poFeature->GetFieldAsInteger64List(i, &nCount);
                    json_object *poArray = json_object_new_array();
                    for (int j = 0; j < nCount; j++)
                        json_object_array_add(
                            poArray, json_object_new_int64(panValues[j]));
                    json_object_object_add(poContainer, pszLastComponent,
                                           poArray);
                    break;
                }
                case OFTRealList:
                {
                    int nCount = 0;
                    const double *padfValues =
                        poFeature->GetFieldAsDoubleList(i, &nCount);
                    json_object *poArray = json_object_new_array();
                    for (int j = 0; j < nCount; j++)
                        json_object_array_add(
                            poArray,
                            json_object_new_double_with_significant_figures(
                                padfValues[j], -1));
                    json_object_object_add(poContainer, pszLastComponent,
                                           poArray);
                    break;
                }
                case OFTStringList:
                {
                    char **papszValues = poFeature->GetFieldAsStringList(i);
                    json_object *poArray = json_object_new_array();
                    for (int j = 0; papszValues[j] != nullptr; j++)
                        json_object_array_add(
                            poArray, json_object_new_string(papszValues[j]));
                    json_object_object_add(poContainer, pszLastComponent,
                                           poArray);
                    break;
                }
                case OFTBinary:
                {
                    int nCount = 0;
                    GByte *pabyVal = poFeature->GetFieldAsBinary(i, &nCount);
                    char *pszVal = CPLBase64Encode(nCount, pabyVal);
                    json_object_object_add(poContainer, pszLastComponent,
                                           json_object_new_string(pszVal));
                    CPLFree(pszVal);
                    break;
                }
                case OFTDateTime:
                {
                    int nYear = 0;
                    int nMonth = 0;
                    int nDay = 0;
                    int nHour = 0;
                    int nMin = 0;
                    int nTZ = 0;
                    float fSec = 0.0f;
                    poFeature->GetFieldAsDateTime(i, &nYear, &nMonth, &nDay,
                                                  &nHour, &nMin, &fSec, &nTZ);
                    if (nTZ == 0)
                    {
                        json_object_object_add(
                            poContainer, pszLastComponent,
                            json_object_new_string(CPLSPrintf(
                                "%04d/%02d/%02d %02d:%02d:%06.3f", nYear,
                                nMonth, nDay, nHour, nMin, fSec)));
                    }
                    else
                    {
                        const int TZOffset = std::abs(nTZ - 100) * 15;
                        const int TZHour = TZOffset / 60;
                        const int TZMinute = TZOffset - TZHour * 60;
                        json_object_object_add(
                            poContainer, pszLastComponent,
                            json_object_new_string(CPLSPrintf(
                                "%04d/%02d/%02d %02d:%02d:%06.3f%c%02d:%02d",
                                nYear, nMonth, nDay, nHour, nMin, fSec,
                                (nTZ >= 100) ? '+' : '-', TZHour, TZMinute)));
                    }
                    break;
                }
                default:
                {
                    const char *pszVal = poFeature->GetFieldAsString(i);
                    json_object_object_add(poContainer, pszLastComponent,
                                           json_object_new_string(pszVal));
                }
            }
        }

        // Build the field string
        fields = json_object_to_json_string(fieldObject);
        json_object_put(fieldObject);
    }

    return fields;
}

/************************************************************************/
/*                          ICreateFeature()                            */
/************************************************************************/

OGRErr OGRElasticLayer::ICreateFeature(OGRFeature *poFeature)
{
    if (m_poDS->GetAccess() != GA_Update)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Dataset opened in read-only mode");
        return OGRERR_FAILURE;
    }

    FinalizeFeatureDefn();

    if (WriteMapIfNecessary() != OGRERR_NONE)
        return OGRERR_FAILURE;

    if (!m_osWriteMapFilename.empty())
        return OGRERR_NONE;

    if (poFeature->GetFID() < 0)
    {
        if (m_nNextFID < 0)
            m_nNextFID = GetFeatureCount(FALSE);
        poFeature->SetFID(++m_nNextFID);
    }

    CPLString osFields(BuildJSonFromFeature(poFeature));

    const char *pszId = nullptr;
    if (poFeature->IsFieldSetAndNotNull(0) && !m_bIgnoreSourceID)
        pszId = poFeature->GetFieldAsString(0);

    // Check to see if we're using bulk uploading
    if (m_nBulkUpload > 0)
    {
        m_osBulkContent +=
            CPLSPrintf("{\"index\" :{\"_index\":\"%s\"", m_osIndexName.c_str());
        if (m_poDS->m_nMajorVersion < 7)
            m_osBulkContent +=
                CPLSPrintf(", \"_type\":\"%s\"", m_osMappingName.c_str());
        if (pszId)
            m_osBulkContent += CPLSPrintf(",\"_id\":\"%s\"", pszId);
        m_osBulkContent += "}}\n" + osFields + "\n\n";

        // Only push the data if we are over our bulk upload limit
        if ((int)m_osBulkContent.length() > m_nBulkUpload)
        {
            if (!PushIndex())
            {
                return OGRERR_FAILURE;
            }
        }
    }
    else
    {
        // Fall back to using single item upload for every feature.
        CPLString osURL(BuildMappingURL(false));
        if (pszId)
            osURL += CPLSPrintf("/%s", pszId);
        json_object *poRes = m_poDS->RunRequest(osURL, osFields);
        if (poRes == nullptr)
        {
            return OGRERR_FAILURE;
        }
        if (pszId == nullptr)
        {
            json_object *poId = CPL_json_object_object_get(poRes, "_id");
            if (poId != nullptr &&
                json_object_get_type(poId) == json_type_string)
            {
                pszId = json_object_get_string(poId);
                poFeature->SetField(0, pszId);
            }
        }
        json_object_put(poRes);
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                           ISetFeature()                              */
/************************************************************************/

OGRErr OGRElasticLayer::ISetFeature(OGRFeature *poFeature)
{
    if (m_poDS->GetAccess() != GA_Update)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Dataset opened in read-only mode");
        return OGRERR_FAILURE;
    }

    FinalizeFeatureDefn();

    if (!poFeature->IsFieldSetAndNotNull(0))
    {
        CPLError(CE_Failure, CPLE_AppDefined, "_id field not set");
        return OGRERR_FAILURE;
    }
    if (poFeature->GetFID() < 0 && !m_osFID.empty())
    {
        CPLError(CE_Failure, CPLE_AppDefined, "Invalid FID");
        return OGRERR_FAILURE;
    }

    if (WriteMapIfNecessary() != OGRERR_NONE)
        return OGRERR_FAILURE;
    PushIndex();

    CPLString osFields(BuildJSonFromFeature(poFeature));

    // TODO? we should theoretically detect if the provided _id doesn't exist
    CPLString osURL(
        CPLSPrintf("%s/%s", m_poDS->GetURL(), m_osIndexName.c_str()));
    if (m_poDS->m_nMajorVersion < 7)
        osURL += CPLSPrintf("/%s", m_osMappingName.c_str());
    osURL += CPLSPrintf("/%s", poFeature->GetFieldAsString(0));
    json_object *poRes = m_poDS->RunRequest(osURL, osFields);
    if (poRes == nullptr)
    {
        return OGRERR_FAILURE;
    }
    // CPLDebug("ES", "SetFeature(): %s", json_object_to_json_string(poRes));
    json_object_put(poRes);

    return OGRERR_NONE;
}

/************************************************************************/
/*                          IUpsertFeature()                            */
/************************************************************************/

OGRErr OGRElasticLayer::IUpsertFeature(OGRFeature *poFeature)
{
    if (m_poDS->GetAccess() != GA_Update)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Dataset opened in read-only mode");
        return OGRERR_FAILURE;
    }

    FinalizeFeatureDefn();

    if (WriteMapIfNecessary() != OGRERR_NONE)
        return OGRERR_FAILURE;

    if (!m_osWriteMapFilename.empty())
        return OGRERR_NONE;

    if (poFeature->GetFID() < 0)
    {
        if (m_nNextFID < 0)
            m_nNextFID = GetFeatureCount(FALSE);
        poFeature->SetFID(++m_nNextFID);
    }

    CPLString osFields(BuildJSonFromFeature(poFeature));

    const char *pszId = nullptr;
    if (poFeature->IsFieldSetAndNotNull(0))
    {
        pszId = poFeature->GetFieldAsString(0);
    }
    else
    {
        return OGRERR_FAILURE;
    }

    // Check to see if we're using bulk uploading
    if (m_nBulkUpload > 0)
    {
        m_osBulkContent +=
            CPLSPrintf("{\"update\":{\"_index\":\"%s\",\"_id\":\"%s\"",
                       m_osIndexName.c_str(), pszId);
        if (m_poDS->m_nMajorVersion < 7)
        {
            m_osBulkContent +=
                CPLSPrintf(", \"_type\":\"%s\"", m_osMappingName.c_str());
        }
        m_osBulkContent +=
            "}}\n{\"doc\":" + osFields + ",\"doc_as_upsert\":true}\n\n";

        // Only push the data if we are over our bulk upload limit
        if (m_osBulkContent.length() > static_cast<size_t>(m_nBulkUpload))
        {
            if (!PushIndex())
            {
                return OGRERR_FAILURE;
            }
        }
    }
    else
    {
        // Fall back to using single item upload for every feature.
        CPLString osURL(BuildMappingURL(false));
        if (m_poDS->m_nMajorVersion < 7)
        {
            osURL += CPLSPrintf("/%s/_update", pszId);
        }
        else
        {
            osURL += CPLSPrintf("/_update/%s", pszId);
        }

        const CPLString osUpdate =
            CPLSPrintf("{\"doc\":%s,\"doc_as_upsert\":true}", osFields.c_str());
        const CPLString osMethod = "POST";
        if (!m_poDS->UploadFile(osURL, osUpdate, osMethod))
        {
            return OGRERR_FAILURE;
        }
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                             PushIndex()                              */
/************************************************************************/

bool OGRElasticLayer::PushIndex()
{
    if (m_osBulkContent.empty())
    {
        return true;
    }

    const bool bRet = m_poDS->UploadFile(
        CPLSPrintf("%s/_bulk", m_poDS->GetURL()), m_osBulkContent);
    m_osBulkContent.clear();

    return bRet;
}

/************************************************************************/
/*                            CreateField()                             */
/************************************************************************/

OGRErr OGRElasticLayer::CreateField(const OGRFieldDefn *poFieldDefn,
                                    int /*bApproxOK*/)
{
    if (m_poDS->GetAccess() != GA_Update)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Dataset opened in read-only mode");
        return OGRERR_FAILURE;
    }

    FinalizeFeatureDefn();
    ResetReading();

    if (m_poFeatureDefn->GetFieldIndex(poFieldDefn->GetNameRef()) >= 0)
    {
        if (!EQUAL(poFieldDefn->GetNameRef(), "_id") &&
            !EQUAL(poFieldDefn->GetNameRef(), "_json"))
        {
            CPLError(
                CE_Failure, CPLE_AppDefined,
                "CreateField() called with an already existing field name: %s",
                poFieldDefn->GetNameRef());
        }
        return OGRERR_FAILURE;
    }

    std::vector<CPLString> aosPath;
    if (m_osMappingName == "FeatureCollection")
        aosPath.push_back("properties");

    if (m_bDotAsNestedField)
    {
        char **papszTokens =
            CSLTokenizeString2(poFieldDefn->GetNameRef(), ".", 0);
        for (int i = 0; papszTokens[i]; i++)
            aosPath.push_back(papszTokens[i]);
        CSLDestroy(papszTokens);
    }
    else
        aosPath.push_back(poFieldDefn->GetNameRef());

    AddFieldDefn(poFieldDefn->GetNameRef(), poFieldDefn->GetType(), aosPath,
                 poFieldDefn->GetSubType());

    m_bSerializeMapping = true;

    return OGRERR_NONE;
}

/************************************************************************/
/*                           CreateGeomField()                          */
/************************************************************************/

OGRErr OGRElasticLayer::CreateGeomField(const OGRGeomFieldDefn *poFieldIn,
                                        int /*bApproxOK*/)

{
    if (m_poDS->GetAccess() != GA_Update)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Dataset opened in read-only mode");
        return OGRERR_FAILURE;
    }

    FinalizeFeatureDefn();
    ResetReading();

    if (m_poFeatureDefn->GetGeomFieldIndex(poFieldIn->GetNameRef()) >= 0)
    {
        CPLError(
            CE_Failure, CPLE_AppDefined,
            "CreateGeomField() called with an already existing field name: %s",
            poFieldIn->GetNameRef());
        return OGRERR_FAILURE;
    }

    OGRGeomFieldDefn oFieldDefn(poFieldIn);
    auto poSRSOri = poFieldIn->GetSpatialRef();
    if (poSRSOri)
    {
        auto poSRS = poSRSOri->Clone();
        poSRS->SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
        oFieldDefn.SetSpatialRef(poSRS);
        poSRS->Release();
    }
    if (EQUAL(oFieldDefn.GetNameRef(), ""))
        oFieldDefn.SetName("geometry");

    std::vector<CPLString> aosPath;
    if (m_bDotAsNestedField)
    {
        char **papszTokens =
            CSLTokenizeString2(oFieldDefn.GetNameRef(), ".", 0);
        for (int i = 0; papszTokens[i]; i++)
            aosPath.push_back(papszTokens[i]);
        CSLDestroy(papszTokens);
    }
    else
        aosPath.push_back(oFieldDefn.GetNameRef());

    if (m_eGeomTypeMapping == ES_GEOMTYPE_GEO_SHAPE ||
        (m_eGeomTypeMapping == ES_GEOMTYPE_AUTO &&
         poFieldIn->GetType() != wkbPoint))
    {
        m_abIsGeoPoint.push_back(FALSE);
    }
    else
    {
        m_abIsGeoPoint.push_back(TRUE);
        aosPath.push_back("coordinates");
    }

    m_aaosGeomFieldPaths.push_back(aosPath);

    m_aosMapToGeomFieldIndex[BuildPathFromArray(aosPath)] =
        m_poFeatureDefn->GetGeomFieldCount();

    m_poFeatureDefn->AddGeomFieldDefn(&oFieldDefn);

    OGRCoordinateTransformation *poCT = nullptr;
    if (oFieldDefn.GetSpatialRef() != nullptr)
    {
        OGRSpatialReference oSRS_WGS84;
        oSRS_WGS84.SetFromUserInput(SRS_WKT_WGS84_LAT_LONG);
        oSRS_WGS84.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);
        if (!oSRS_WGS84.IsSame(oFieldDefn.GetSpatialRef()))
        {
            poCT = OGRCreateCoordinateTransformation(oFieldDefn.GetSpatialRef(),
                                                     &oSRS_WGS84);
            if (poCT == nullptr)
            {
                CPLError(CE_Warning, CPLE_AppDefined,
                         "On-the-fly reprojection to WGS84 long/lat would be "
                         "needed, but instantiation of transformer failed");
            }
        }
    }
    else
    {
        CPLError(CE_Warning, CPLE_AppDefined,
                 "No SRS given for geometry column %s. SRS is assumed to "
                 "be EPSG:4326 (WGS84 long/lat)",
                 oFieldDefn.GetNameRef());
    }

    m_apoCT.push_back(poCT);

    m_bSerializeMapping = true;

    return OGRERR_NONE;
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRElasticLayer::TestCapability(const char *pszCap) const
{
    if (EQUAL(pszCap, OLCFastFeatureCount))
        return m_poAttrQuery == nullptr && m_poFilterGeom == nullptr;

    else if (EQUAL(pszCap, OLCStringsAsUTF8))
        return TRUE;

    else if (EQUAL(pszCap, OLCSequentialWrite) ||
             EQUAL(pszCap, OLCUpsertFeature) || EQUAL(pszCap, OLCRandomWrite))
        return m_poDS->GetAccess() == GA_Update;
    else if (EQUAL(pszCap, OLCCreateField) || EQUAL(pszCap, OLCCreateGeomField))
        return m_poDS->GetAccess() == GA_Update;
    else
        return FALSE;
}

/************************************************************************/
/*                   AddTimeoutTerminateAfterToURL()                    */
/************************************************************************/

void OGRElasticLayer::AddTimeoutTerminateAfterToURL(CPLString &osURL)
{
    if (!m_osSingleQueryTimeout.empty())
        osURL += "&timeout=" + m_osSingleQueryTimeout;
    if (!m_osSingleQueryTerminateAfter.empty())
        osURL += "&terminate_after=" + m_osSingleQueryTerminateAfter;
}

/************************************************************************/
/*                          GetFeatureCount()                           */
/************************************************************************/

GIntBig OGRElasticLayer::GetFeatureCount(int bForce)
{
    if (m_bFilterMustBeClientSideEvaluated)
    {
        m_bUseSingleQueryParams = true;
        const auto nRet = OGRLayer::GetFeatureCount(bForce);
        m_bUseSingleQueryParams = false;
        return nRet;
    }

    json_object *poResponse = nullptr;
    CPLString osURL(CPLSPrintf("%s", m_poDS->GetURL()));
    CPLString osFilter = "";
    if (!m_osESSearch.empty())
    {
        if (m_osESSearch[0] != '{')
            return OGRLayer::GetFeatureCount(bForce);
        osURL += "/_search?pretty";
        osFilter = "{ \"size\": 0 ";
        if (m_osESSearch == "{}")
            osFilter += '}';
        else
            osFilter += ", " + m_osESSearch.substr(1);
    }
    else if ((m_poSpatialFilter && m_osJSONFilter.empty()) || m_poJSONFilter)
    {
        osFilter = BuildQuery(true);
        osURL += CPLSPrintf("/%s", m_osIndexName.c_str());
        if (m_poDS->m_nMajorVersion < 7)
            osURL += CPLSPrintf("/%s", m_osMappingName.c_str());
        if (m_poDS->m_nMajorVersion >= 5 && m_osSingleQueryTimeout.empty())
        {
            osURL += "/_count?pretty";
        }
        else
        {
            osURL += "/_search?pretty";
        }
    }
    else if (!m_osJSONFilter.empty())
    {
        osURL += CPLSPrintf("/%s", m_osIndexName.c_str());
        if (m_poDS->m_nMajorVersion < 7)
            osURL += CPLSPrintf("/%s", m_osMappingName.c_str());
        osURL += "/_search?pretty";
        osFilter = ("{ \"size\": 0, " + m_osJSONFilter.substr(1));
    }
    else
    {
        osURL += CPLSPrintf("/%s", m_osIndexName.c_str());
        if (m_poDS->m_nMajorVersion < 7)
            osURL += CPLSPrintf("/%s", m_osMappingName.c_str());
        if (m_osSingleQueryTimeout.empty())
        {
            osURL += "/_count?pretty";
        }
        else
        {
            osFilter = "{ \"size\": 0 }";
            osURL += CPLSPrintf("/_search?pretty");
        }
    }
    AddTimeoutTerminateAfterToURL(osURL);

    poResponse = m_poDS->RunRequest(osURL.c_str(), osFilter.c_str());

    json_object *poCount = json_ex_get_object_by_path(poResponse, "hits.count");
    if (poCount == nullptr)
    {
        // For _search request
        poCount = json_ex_get_object_by_path(poResponse, "hits.total");
        if (poCount && json_object_get_type(poCount) == json_type_object)
        {
            // Since ES 7.0
            poCount = json_ex_get_object_by_path(poCount, "value");
        }
    }
    if (poCount == nullptr)
    {
        // For _count request
        poCount = json_ex_get_object_by_path(poResponse, "count");
    }
    if (poCount == nullptr || json_object_get_type(poCount) != json_type_int)
    {
        json_object_put(poResponse);
        CPLDebug("ES", "Cannot find hits in GetFeatureCount() response. "
                       "Falling back to slow implementation");
        m_bUseSingleQueryParams = true;
        const auto nRet = OGRLayer::GetFeatureCount(bForce);
        m_bUseSingleQueryParams = false;
        return nRet;
    }

    GIntBig nCount = json_object_get_int64(poCount);
    json_object_put(poResponse);
    return nCount;
}

/************************************************************************/
/*                            GetValue()                                */
/************************************************************************/

json_object *OGRElasticLayer::GetValue(int nFieldIdx, swq_expr_node *poValNode)
{
    json_object *poVal = nullptr;
    if (poValNode->field_type == SWQ_FLOAT)
        poVal = json_object_new_double(poValNode->float_value);
    else if (poValNode->field_type == SWQ_INTEGER ||
             poValNode->field_type == SWQ_INTEGER64)
        poVal = json_object_new_int64(poValNode->int_value);
    else if (poValNode->field_type == SWQ_STRING)
        poVal = json_object_new_string(poValNode->string_value);
    else if (poValNode->field_type == SWQ_TIMESTAMP)
    {
        int nYear = 0;
        int nMonth = 0;
        int nDay = 0;
        int nHour = 0;
        int nMinute = 0;
        float fSecond = 0;
        if (sscanf(poValNode->string_value, "%04d/%02d/%02d %02d:%02d:%f",
                   &nYear, &nMonth, &nDay, &nHour, &nMinute, &fSecond) >= 3 ||
            sscanf(poValNode->string_value, "%04d-%02d-%02dT%02d:%02d:%f",
                   &nYear, &nMonth, &nDay, &nHour, &nMinute, &fSecond) >= 3)
        {
            OGRFieldType eType(
                m_poFeatureDefn->GetFieldDefn(nFieldIdx)->GetType());
            if (eType == OFTDateTime)
                poVal = json_object_new_string(
                    CPLSPrintf("%04d/%02d/%02d %02d:%02d:%02.03f", nYear,
                               nMonth, nDay, nHour, nMinute, fSecond));
            else if (eType == OFTDate)
                poVal = json_object_new_string(
                    CPLSPrintf("%04d/%02d/%02d", nYear, nMonth, nDay));
            else
                poVal = json_object_new_string(
                    CPLSPrintf("%02d:%02d:%02.03f", nHour, nMinute, fSecond));
        }
        else
        {
            return nullptr;
        }
    }
    else
    {
        CPLError(CE_Failure, CPLE_NotSupported, "Unhandled type: %d",
                 poValNode->field_type);
    }
    return poVal;
}

/************************************************************************/
/*                      OGRESGetFieldIndexFromSQL()                     */
/************************************************************************/

static int OGRESGetFieldIndexFromSQL(const swq_expr_node *poNode)
{
    if (poNode->eNodeType == SNT_COLUMN)
        return poNode->field_index;

    if (poNode->eNodeType == SNT_OPERATION && poNode->nOperation == SWQ_CAST &&
        poNode->nSubExprCount >= 1 &&
        poNode->papoSubExpr[0]->eNodeType == SNT_COLUMN)
        return poNode->papoSubExpr[0]->field_index;

    return -1;
}

/************************************************************************/
/*                        TranslateSQLToFilter()                        */
/************************************************************************/

json_object *OGRElasticLayer::TranslateSQLToFilter(swq_expr_node *poNode)
{
    if (poNode->eNodeType == SNT_OPERATION)
    {
        int nFieldIdx = 0;
        CPL_IGNORE_RET_VAL(nFieldIdx);  // to make cppcheck happy
        if (poNode->nOperation == SWQ_AND && poNode->nSubExprCount == 2)
        {
            // For AND, we can deal with a failure in one of the branch
            // since client-side will do that extra filtering
            json_object *poFilter1 =
                TranslateSQLToFilter(poNode->papoSubExpr[0]);
            json_object *poFilter2 =
                TranslateSQLToFilter(poNode->papoSubExpr[1]);
            if (poFilter1 && poFilter2)
            {
                json_object *poRet = json_object_new_object();
                json_object *poBool = json_object_new_object();
                json_object_object_add(poRet, "bool", poBool);
                json_object *poMust = json_object_new_array();
                json_object_object_add(poBool, "must", poMust);
                json_object_array_add(poMust, poFilter1);
                json_object_array_add(poMust, poFilter2);
                return poRet;
            }
            else if (poFilter1)
                return poFilter1;
            else
                return poFilter2;
        }
        else if (poNode->nOperation == SWQ_OR && poNode->nSubExprCount == 2)
        {
            json_object *poFilter1 =
                TranslateSQLToFilter(poNode->papoSubExpr[0]);
            json_object *poFilter2 =
                TranslateSQLToFilter(poNode->papoSubExpr[1]);
            if (poFilter1 && poFilter2)
            {
                json_object *poRet = json_object_new_object();
                json_object *poBool = json_object_new_object();
                json_object_object_add(poRet, "bool", poBool);
                json_object *poShould = json_object_new_array();
                json_object_object_add(poBool, "should", poShould);
                json_object_array_add(poShould, poFilter1);
                json_object_array_add(poShould, poFilter2);
                return poRet;
            }
            else
            {
                json_object_put(poFilter1);
                json_object_put(poFilter2);
                return nullptr;
            }
        }
        else if (poNode->nOperation == SWQ_NOT && poNode->nSubExprCount == 1)
        {
            if (poNode->papoSubExpr[0]->eNodeType == SNT_OPERATION &&
                poNode->papoSubExpr[0]->nOperation == SWQ_ISNULL &&
                poNode->papoSubExpr[0]->nSubExprCount == 1 &&
                poNode->papoSubExpr[0]->papoSubExpr[0]->field_index != 0 &&
                poNode->papoSubExpr[0]->papoSubExpr[0]->field_index <
                    m_poFeatureDefn->GetFieldCount())
            {
                json_object *poRet = json_object_new_object();
                json_object *poExists = json_object_new_object();
                CPLString osFieldName(BuildPathFromArray(
                    m_aaosFieldPaths
                        [poNode->papoSubExpr[0]->papoSubExpr[0]->field_index]));
                json_object_object_add(poExists, "field",
                                       json_object_new_string(osFieldName));
                json_object_object_add(poRet, "exists", poExists);
                return poRet;
            }
            else
            {
                json_object *poFilter =
                    TranslateSQLToFilter(poNode->papoSubExpr[0]);
                if (poFilter)
                {
                    json_object *poRet = json_object_new_object();
                    json_object *poBool = json_object_new_object();
                    json_object_object_add(poRet, "bool", poBool);
                    json_object_object_add(poBool, "must_not", poFilter);
                    return poRet;
                }
                else
                {
                    return nullptr;
                }
            }
        }
        else if (poNode->nOperation == SWQ_ISNULL &&
                 poNode->nSubExprCount == 1 &&
                 (nFieldIdx =
                      OGRESGetFieldIndexFromSQL(poNode->papoSubExpr[0])) > 0 &&
                 nFieldIdx < m_poFeatureDefn->GetFieldCount())
        {
            json_object *poRet = json_object_new_object();
            json_object *poExists = json_object_new_object();
            CPLString osFieldName(
                BuildPathFromArray(m_aaosFieldPaths[nFieldIdx]));
            json_object_object_add(poExists, "field",
                                   json_object_new_string(osFieldName));
            json_object *poBool = json_object_new_object();
            json_object_object_add(poRet, "bool", poBool);
            json_object *poMustNot = json_object_new_object();
            json_object_object_add(poMustNot, "exists", poExists);
            json_object_object_add(poBool, "must_not", poMustNot);
            return poRet;
        }
        else if (poNode->nOperation == SWQ_NE)
        {
            poNode->nOperation = SWQ_EQ;
            json_object *poFilter = TranslateSQLToFilter(poNode);
            poNode->nOperation = SWQ_NE;
            if (poFilter)
            {
                json_object *poRet = json_object_new_object();
                json_object *poBool = json_object_new_object();
                json_object_object_add(poRet, "bool", poBool);
                json_object_object_add(poBool, "must_not", poFilter);
                return poRet;
            }
            else
            {
                return nullptr;
            }
        }
        else if (poNode->nOperation == SWQ_EQ && poNode->nSubExprCount == 2 &&
                 poNode->papoSubExpr[1]->eNodeType == SNT_CONSTANT &&
                 (nFieldIdx =
                      OGRESGetFieldIndexFromSQL(poNode->papoSubExpr[0])) >= 0 &&
                 nFieldIdx < m_poFeatureDefn->GetFieldCount())
        {
            json_object *poVal = GetValue(nFieldIdx, poNode->papoSubExpr[1]);
            if (poVal == nullptr)
            {
                return nullptr;
            }
            json_object *poRet = json_object_new_object();
            if (nFieldIdx == 0)
            {
                json_object *poIds = json_object_new_object();
                json_object *poValues = json_object_new_array();
                json_object_object_add(poIds, "values", poValues);
                json_object_array_add(poValues, poVal);
                json_object_object_add(poRet, "ids", poIds);
            }
            else
            {
                json_object *poTerm = json_object_new_object();
                CPLString osPath(
                    BuildPathFromArray(m_aaosFieldPaths[nFieldIdx]));
                bool bNotAnalyzed = true;
                if (poNode->papoSubExpr[1]->field_type == SWQ_STRING)
                {
                    const char *pszFieldName =
                        m_poFeatureDefn->GetFieldDefn(nFieldIdx)->GetNameRef();
                    bNotAnalyzed = CSLFindString(m_papszNotAnalyzedFields,
                                                 pszFieldName) >= 0;
                    if (!bNotAnalyzed)
                    {
                        if (CSLFindString(m_papszFieldsWithRawValue,
                                          pszFieldName) >= 0)
                        {
                            osPath += ".raw";
                            bNotAnalyzed = true;
                        }
                        else if (!m_bFilterMustBeClientSideEvaluated)
                        {
                            m_bFilterMustBeClientSideEvaluated = true;
                            CPLDebug("ES",
                                     "Part or full filter will have to be "
                                     "evaluated on "
                                     "client side (equality test on a analyzed "
                                     "field).");
                        }
                    }
                }
                json_object_object_add(poRet, bNotAnalyzed ? "term" : "match",
                                       poTerm);
                json_object_object_add(poTerm, osPath, poVal);

                if (!bNotAnalyzed && m_poDS->m_nMajorVersion < 2)
                {
                    json_object *poNewRet = json_object_new_object();
                    json_object_object_add(poNewRet, "query", poRet);
                    poRet = poNewRet;
                }
            }
            return poRet;
        }
        else if ((poNode->nOperation == SWQ_LT ||
                  poNode->nOperation == SWQ_LE ||
                  poNode->nOperation == SWQ_GT ||
                  poNode->nOperation == SWQ_GE) &&
                 poNode->nSubExprCount == 2 &&
                 poNode->papoSubExpr[1]->eNodeType == SNT_CONSTANT &&
                 (nFieldIdx =
                      OGRESGetFieldIndexFromSQL(poNode->papoSubExpr[0])) > 0 &&
                 nFieldIdx < m_poFeatureDefn->GetFieldCount())
        {
            json_object *poVal = GetValue(nFieldIdx, poNode->papoSubExpr[1]);
            if (poVal == nullptr)
            {
                return nullptr;
            }
            json_object *poRet = json_object_new_object();
            json_object *poRange = json_object_new_object();
            json_object_object_add(poRet, "range", poRange);
            json_object *poFieldConstraint = json_object_new_object();
            CPLString osFieldName(
                BuildPathFromArray(m_aaosFieldPaths[nFieldIdx]));
            json_object_object_add(poRange, osFieldName, poFieldConstraint);
            const char *pszOp = (poNode->nOperation == SWQ_LT)   ? "lt"
                                : (poNode->nOperation == SWQ_LE) ? "lte"
                                : (poNode->nOperation == SWQ_GT)
                                    ? "gt"
                                    :
                                    /*(poNode->nOperation == SWQ_GE) ?*/ "gte";
            json_object_object_add(poFieldConstraint, pszOp, poVal);
            return poRet;
        }
        else if (poNode->nOperation == SWQ_BETWEEN &&
                 poNode->nSubExprCount == 3 &&
                 poNode->papoSubExpr[1]->eNodeType == SNT_CONSTANT &&
                 poNode->papoSubExpr[2]->eNodeType == SNT_CONSTANT &&
                 (nFieldIdx =
                      OGRESGetFieldIndexFromSQL(poNode->papoSubExpr[0])) > 0 &&
                 nFieldIdx < m_poFeatureDefn->GetFieldCount())
        {
            json_object *poVal1 = GetValue(nFieldIdx, poNode->papoSubExpr[1]);
            if (poVal1 == nullptr)
            {
                return nullptr;
            }
            json_object *poVal2 = GetValue(nFieldIdx, poNode->papoSubExpr[2]);
            if (poVal2 == nullptr)
            {
                json_object_put(poVal1);
                return nullptr;
            }

            json_object *poRet = json_object_new_object();
            json_object *poRange = json_object_new_object();
            json_object_object_add(poRet, "range", poRange);
            json_object *poFieldConstraint = json_object_new_object();
            CPLString osFieldName(
                BuildPathFromArray(m_aaosFieldPaths[nFieldIdx]));
            json_object_object_add(poRange, osFieldName, poFieldConstraint);
            json_object_object_add(poFieldConstraint, "gte", poVal1);
            json_object_object_add(poFieldConstraint, "lte", poVal2);
            return poRet;
        }
        else if (poNode->nOperation == SWQ_IN && poNode->nSubExprCount > 1 &&
                 (nFieldIdx =
                      OGRESGetFieldIndexFromSQL(poNode->papoSubExpr[0])) >= 0 &&
                 nFieldIdx < m_poFeatureDefn->GetFieldCount())
        {
            bool bAllConstant = true;
            for (int i = 1; i < poNode->nSubExprCount; i++)
            {
                if (poNode->papoSubExpr[i]->eNodeType != SNT_CONSTANT)
                {
                    bAllConstant = false;
                    break;
                }
            }
            if (bAllConstant)
            {
                json_object *poRet = json_object_new_object();
                if (nFieldIdx == 0)
                {
                    json_object *poIds = json_object_new_object();
                    json_object *poValues = json_object_new_array();
                    json_object_object_add(poIds, "values", poValues);
                    json_object_object_add(poRet, "ids", poIds);
                    for (int i = 1; i < poNode->nSubExprCount; i++)
                    {
                        json_object *poVal =
                            GetValue(nFieldIdx, poNode->papoSubExpr[i]);
                        if (poVal == nullptr)
                        {
                            json_object_put(poRet);
                            return nullptr;
                        }
                        json_object_array_add(poValues, poVal);
                    }
                }
                else
                {
                    bool bNotAnalyzed = true;
                    CPLString osPath(
                        BuildPathFromArray(m_aaosFieldPaths[nFieldIdx]));
                    if (poNode->papoSubExpr[1]->field_type == SWQ_STRING)
                    {
                        const char *pszFieldName =
                            m_poFeatureDefn->GetFieldDefn(nFieldIdx)
                                ->GetNameRef();
                        bNotAnalyzed = CSLFindString(m_papszNotAnalyzedFields,
                                                     pszFieldName) >= 0;
                        if (!bNotAnalyzed &&
                            CSLFindString(m_papszFieldsWithRawValue,
                                          pszFieldName) >= 0)
                        {
                            osPath += ".raw";
                            bNotAnalyzed = true;
                        }

                        if (!bNotAnalyzed &&
                            !m_bFilterMustBeClientSideEvaluated)
                        {
                            m_bFilterMustBeClientSideEvaluated = true;
                            CPLDebug("ES",
                                     "Part or full filter will have to be "
                                     "evaluated on client side (IN test on a "
                                     "analyzed field).");
                        }
                    }

                    if (bNotAnalyzed)
                    {
                        json_object *poTerms = json_object_new_object();
                        json_object_object_add(poRet, "terms", poTerms);
                        json_object *poTermsValues = json_object_new_array();
                        json_object_object_add(poTerms, osPath, poTermsValues);
                        for (int i = 1; i < poNode->nSubExprCount; i++)
                        {
                            json_object *poVal =
                                GetValue(nFieldIdx, poNode->papoSubExpr[i]);
                            if (poVal == nullptr)
                            {
                                json_object_put(poRet);
                                return nullptr;
                            }
                            json_object_array_add(poTermsValues, poVal);
                        }
                    }
                    else
                    {
                        json_object *poBool = json_object_new_object();
                        json_object_object_add(poRet, "bool", poBool);
                        json_object *poShould = json_object_new_array();
                        json_object_object_add(poBool, "should", poShould);
                        for (int i = 1; i < poNode->nSubExprCount; i++)
                        {
                            json_object *poVal =
                                GetValue(nFieldIdx, poNode->papoSubExpr[i]);
                            if (poVal == nullptr)
                            {
                                json_object_put(poRet);
                                return nullptr;
                            }
                            json_object *poShouldElt = json_object_new_object();
                            json_object *poMatch = json_object_new_object();
                            json_object_object_add(poShouldElt, "match",
                                                   poMatch);
                            json_object_object_add(poMatch, osPath, poVal);

                            if (m_poDS->m_nMajorVersion < 2)
                            {
                                json_object *poNewShouldElt =
                                    json_object_new_object();
                                json_object_object_add(poNewShouldElt, "query",
                                                       poShouldElt);
                                poShouldElt = poNewShouldElt;
                            }
                            json_object_array_add(poShould, poShouldElt);
                        }
                    }
                }
                return poRet;
            }
        }
        else if ((poNode->nOperation == SWQ_LIKE ||
                  poNode->nOperation ==
                      SWQ_ILIKE) &&  // ES actual semantics doesn't match
                                     // exactly either...
                 poNode->nSubExprCount >= 2 &&
                 (nFieldIdx =
                      OGRESGetFieldIndexFromSQL(poNode->papoSubExpr[0])) > 0 &&
                 nFieldIdx < m_poFeatureDefn->GetFieldCount())
        {
            char chEscape = '\0';
            if (poNode->nSubExprCount == 3)
                chEscape = poNode->papoSubExpr[2]->string_value[0];
            const char *pszPattern = poNode->papoSubExpr[1]->string_value;
            const char *pszFieldName =
                m_poFeatureDefn->GetFieldDefn(nFieldIdx)->GetNameRef();
            bool bNotAnalyzed =
                CSLFindString(m_papszNotAnalyzedFields, pszFieldName) >= 0;
            CPLString osPath(BuildPathFromArray(m_aaosFieldPaths[nFieldIdx]));
            if (!bNotAnalyzed &&
                CSLFindString(m_papszFieldsWithRawValue, pszFieldName) >= 0)
            {
                osPath += ".raw";
                bNotAnalyzed = true;
            }

            if (strchr(pszPattern, '*') || strchr(pszPattern, '?'))
            {
                CPLDebug("ES", "Cannot handle * or ? in LIKE pattern");
            }
            else if (!bNotAnalyzed)
            {
                if (!m_bFilterMustBeClientSideEvaluated)
                {
                    m_bFilterMustBeClientSideEvaluated = true;
                    CPLDebug(
                        "ES",
                        "Part or full filter will have to be evaluated on "
                        "client side (wildcard test on a analyzed field).");
                }
            }
            else
            {
                CPLString osUnescaped;
                for (int i = 0; pszPattern[i] != '\0'; ++i)
                {
                    if (chEscape == pszPattern[i])
                    {
                        if (pszPattern[i + 1] == '\0')
                            break;
                        osUnescaped += pszPattern[i + 1];
                        i++;
                    }
                    else if (pszPattern[i] == '%')
                    {
                        osUnescaped += '*';
                    }
                    else if (pszPattern[i] == '_')
                    {
                        osUnescaped += '?';
                    }
                    else
                    {
                        osUnescaped += pszPattern[i];
                    }
                }
                json_object *poRet = json_object_new_object();
                json_object *poWildcard = json_object_new_object();
                json_object_object_add(poRet, "wildcard", poWildcard);
                json_object_object_add(poWildcard, osPath,
                                       json_object_new_string(osUnescaped));
                return poRet;
            }
        }
    }

    if (!m_bFilterMustBeClientSideEvaluated)
    {
        m_bFilterMustBeClientSideEvaluated = true;
        CPLDebug("ES", "Part or full filter will have to be evaluated on "
                       "client side.");
    }
    return nullptr;
}

/************************************************************************/
/*                          SetAttributeFilter()                        */
/************************************************************************/

OGRErr OGRElasticLayer::SetAttributeFilter(const char *pszFilter)
{
    m_bFilterMustBeClientSideEvaluated = false;
    if (pszFilter != nullptr && pszFilter[0] == '{')
    {
        if (!m_osESSearch.empty())
        {
            CPLError(CE_Failure, CPLE_AppDefined,
                     "Setting an Elasticsearch filter on a resulting layer "
                     "is not supported");
            return OGRERR_FAILURE;
        }
        OGRLayer::SetAttributeFilter(nullptr);
        m_osJSONFilter = pszFilter;
        return OGRERR_NONE;
    }
    else
    {
        m_osJSONFilter.clear();
        json_object_put(m_poJSONFilter);
        m_poJSONFilter = nullptr;
        OGRErr eErr = OGRLayer::SetAttributeFilter(pszFilter);
        if (eErr == OGRERR_NONE && m_poAttrQuery != nullptr)
        {
            swq_expr_node *poNode =
                reinterpret_cast<swq_expr_node *>(m_poAttrQuery->GetSWQExpr());
            m_poJSONFilter = TranslateSQLToFilter(poNode);
        }
        return eErr;
    }
}

/************************************************************************/
/*                          ClampEnvelope()                             */
/************************************************************************/

void OGRElasticLayer::ClampEnvelope(OGREnvelope &sEnvelope)
{
    if (sEnvelope.MinX < -180)
        sEnvelope.MinX = -180;
    if (sEnvelope.MinX > 180)
        sEnvelope.MinX = 180;

    if (sEnvelope.MinY < -90)
        sEnvelope.MinY = -90;
    if (sEnvelope.MinY > 90)
        sEnvelope.MinY = 90;

    if (sEnvelope.MaxX > 180)
        sEnvelope.MaxX = 180;
    if (sEnvelope.MaxX < -180)
        sEnvelope.MaxX = -180;

    if (sEnvelope.MaxY > 90)
        sEnvelope.MaxY = 90;
    if (sEnvelope.MaxY < -90)
        sEnvelope.MaxY = -90;
}

/************************************************************************/
/*                          ISetSpatialFilter()                         */
/************************************************************************/

OGRErr OGRElasticLayer::ISetSpatialFilter(int iGeomField,
                                          const OGRGeometry *poGeomIn)

{
    FinalizeFeatureDefn();

    m_iGeomFieldFilter = iGeomField;

    InstallFilter(poGeomIn);

    json_object_put(m_poSpatialFilter);
    m_poSpatialFilter = nullptr;

    if (poGeomIn == nullptr)
        return OGRERR_NONE;

    if (!m_osESSearch.empty())
    {
        CPLError(
            CE_Failure, CPLE_AppDefined,
            "Setting a spatial filter on a resulting layer is not supported");
        return OGRERR_FAILURE;
    }

    OGREnvelope sEnvelope;
    poGeomIn->getEnvelope(&sEnvelope);
    ClampEnvelope(sEnvelope);

    if (sEnvelope.MinX == -180 && sEnvelope.MinY == -90 &&
        sEnvelope.MaxX == 180 && sEnvelope.MaxY == 90)
    {
        return OGRERR_NONE;
    }

    m_poSpatialFilter = json_object_new_object();

    if (m_abIsGeoPoint[iGeomField])
    {
        json_object *geo_bounding_box = json_object_new_object();
        json_object_object_add(m_poSpatialFilter, "geo_bounding_box",
                               geo_bounding_box);

        CPLString osPath = BuildPathFromArray(m_aaosGeomFieldPaths[iGeomField]);

        json_object *field = json_object_new_object();
        json_object_object_add(geo_bounding_box, osPath.c_str(), field);

        json_object *top_left = json_object_new_object();
        json_object_object_add(field, "top_left", top_left);
        json_object_object_add(
            top_left, "lat",
            json_object_new_double_with_precision(sEnvelope.MaxY, 6));
        json_object_object_add(
            top_left, "lon",
            json_object_new_double_with_precision(sEnvelope.MinX, 6));

        json_object *bottom_right = json_object_new_object();
        json_object_object_add(field, "bottom_right", bottom_right);
        json_object_object_add(
            bottom_right, "lat",
            json_object_new_double_with_precision(sEnvelope.MinY, 6));
        json_object_object_add(
            bottom_right, "lon",
            json_object_new_double_with_precision(sEnvelope.MaxX, 6));
    }
    else
    {
        json_object *geo_shape = json_object_new_object();
        json_object_object_add(m_poSpatialFilter, "geo_shape", geo_shape);

        CPLString osPath = BuildPathFromArray(m_aaosGeomFieldPaths[iGeomField]);

        json_object *field = json_object_new_object();
        json_object_object_add(geo_shape, osPath.c_str(), field);

        json_object *shape = json_object_new_object();
        json_object_object_add(field, "shape", shape);

        json_object_object_add(shape, "type",
                               json_object_new_string("envelope"));

        json_object *coordinates = json_object_new_array();
        json_object_object_add(shape, "coordinates", coordinates);

        json_object *top_left = json_object_new_array();
        json_object_array_add(
            top_left, json_object_new_double_with_precision(sEnvelope.MinX, 6));
        json_object_array_add(
            top_left, json_object_new_double_with_precision(sEnvelope.MaxY, 6));
        json_object_array_add(coordinates, top_left);

        json_object *bottom_right = json_object_new_array();
        json_object_array_add(
            bottom_right,
            json_object_new_double_with_precision(sEnvelope.MaxX, 6));
        json_object_array_add(
            bottom_right,
            json_object_new_double_with_precision(sEnvelope.MinY, 6));
        json_object_array_add(coordinates, bottom_right);
    }

    return OGRERR_NONE;
}

/************************************************************************/
/*                           IGetExtent()                                */
/************************************************************************/

OGRErr OGRElasticLayer::IGetExtent(int iGeomField, OGREnvelope *psExtent,
                                   bool bForce)
{
    FinalizeFeatureDefn();

    // geo_shape aggregation is only available since ES 7.8, but only with XPack
    // for now
    if (!m_abIsGeoPoint[iGeomField] &&
        !(m_poDS->m_nMajorVersion > 7 ||
          (m_poDS->m_nMajorVersion == 7 && m_poDS->m_nMinorVersion >= 8)))
    {
        m_bUseSingleQueryParams = true;
        const auto eRet = OGRLayer::IGetExtent(iGeomField, psExtent, bForce);
        m_bUseSingleQueryParams = false;
        return eRet;
    }

    CPLString osFilter = CPLSPrintf(
        "{ \"size\": 0, \"aggs\" : { \"bbox\" : { \"geo_bounds\" : { \"field\" "
        ": \"%s\" } } } }",
        BuildPathFromArray(m_aaosGeomFieldPaths[iGeomField]).c_str());
    CPLString osURL =
        CPLSPrintf("%s/%s", m_poDS->GetURL(), m_osIndexName.c_str());
    if (m_poDS->m_nMajorVersion < 7)
        osURL += CPLSPrintf("/%s", m_osMappingName.c_str());
    osURL += "/_search?pretty";
    AddTimeoutTerminateAfterToURL(osURL);

    CPLPushErrorHandler(CPLQuietErrorHandler);
    json_object *poResponse =
        m_poDS->RunRequest(osURL.c_str(), osFilter.c_str());
    CPLPopErrorHandler();
    if (poResponse == nullptr)
    {
        const char *pszLastErrorMsg = CPLGetLastErrorMsg();
        if (!m_abIsGeoPoint[iGeomField] &&
            strstr(pszLastErrorMsg, "Fielddata is not supported on field") !=
                nullptr)
        {
            CPLDebug("ES",
                     "geo_bounds aggregation failed, likely because of lack "
                     "of XPack. Using client-side method");
            CPLErrorReset();
        }
        else
        {
            CPLError(CE_Failure, CPLE_AppDefined, "%s", pszLastErrorMsg);
        }
    }

    json_object *poBounds =
        json_ex_get_object_by_path(poResponse, "aggregations.bbox.bounds");
    json_object *poTopLeft = json_ex_get_object_by_path(poBounds, "top_left");
    json_object *poBottomRight =
        json_ex_get_object_by_path(poBounds, "bottom_right");
    json_object *poTopLeftLon = json_ex_get_object_by_path(poTopLeft, "lon");
    json_object *poTopLeftLat = json_ex_get_object_by_path(poTopLeft, "lat");
    json_object *poBottomRightLon =
        json_ex_get_object_by_path(poBottomRight, "lon");
    json_object *poBottomRightLat =
        json_ex_get_object_by_path(poBottomRight, "lat");

    OGRErr eErr;
    if (poTopLeftLon == nullptr || poTopLeftLat == nullptr ||
        poBottomRightLon == nullptr || poBottomRightLat == nullptr)
    {
        m_bUseSingleQueryParams = true;
        const auto eRet = OGRLayer::IGetExtent(iGeomField, psExtent, bForce);
        m_bUseSingleQueryParams = false;
        return eRet;
    }
    else
    {
        double dfMinX = json_object_get_double(poTopLeftLon);
        double dfMaxY = json_object_get_double(poTopLeftLat);
        double dfMaxX = json_object_get_double(poBottomRightLon);
        double dfMinY = json_object_get_double(poBottomRightLat);

        psExtent->MinX = dfMinX;
        psExtent->MaxY = dfMaxY;
        psExtent->MaxX = dfMaxX;
        psExtent->MinY = dfMinY;

        eErr = OGRERR_NONE;
    }
    json_object_put(poResponse);

    return eErr;
}

/************************************************************************/
/*                             GetDataset()                             */
/************************************************************************/

GDALDataset *OGRElasticLayer::GetDataset()
{
    return m_poDS;
}
